Biomedical subjects

M J Druse

Publications and source records attributed to M J Druse.

At least 19 recordsLinked to original sources

PubMed2001

Astrocyte-mediated trophic support of developing serotonin neurons: effects of ethanol, buspirone, and S100B.

Previously, this laboratory demonstrated that the development of serotonin (5-HT) neurons and S100B-immunopositive glia proximal to these neurons is impaired in the offspring of ethanol-fed rats. However, maternal treatment with a 5-HT(1A) agonist, e.g., buspirone or ipsapirone, between gestational days 13 and 20 prevented most of the ethanol-associated changes to developing 5-HT neurons and S100B-immunopositive glia in offspring. The present in vitro studies examined the hypothesis that the protective effects of a 5-HT(1A) agonist on ethanol-exposed, developing 5-HT neurons are mediated in part by astrocyte-produced factors such as S100B. Primary cultures of fetal 5-HT neurons were maintained in conditioned medium (CM) that was obtained from ethanol- and buspirone-treated astrocytes. In order to assess the potential contribution of S100B to the protective effects of buspirone, a mouse monoclonal antibody to S100B was added to the CM to block the biological effects of this protein. These studies demonstrated that CM, obtained from ethanol-treated astrocytes, was unable to support normal development of 5-HT neurons; there was a significant reduction in the number of 5-HT neurons/well. However, CM that was obtained from astrocytes that were co-treated with buspirone and ethanol prevented the ethanol-associated reduction, and the protective effects of buspirone required S100B. We also investigated whether exogenous S100B could protect 5-HT neurons from damage caused by direct exposure to ethanol. Direct exposure of fetal brainstem neurons to ethanol in chemically-defined medium was associated with a significant reduction in the number of 5-HT immunopositive neurons/well. However, exogenous S100B protected 5-HT neurons from the ethanol-associated reduction. Our observations suggest that the protective effects of buspirone on ethanol-exposed, developing 5-HT neurons are mediated in part by the astrocyte-produced factor S100B.

Animals↗

PubMed2001

A persistent deficit of serotonin neurons in the offspring of ethanol-fed dams: protective effects of maternal ipsapirone treatment.

An earlier study from this laboratory found a significant reduction in the density of serotonin (5-HT) neurons in the dorsal and median raphe and in the B9 complex of postnatal day 5 (PN5) offspring of female rats that consumed ethanol on a chronic basis prior to parturition. In addition, we demonstrated that maternal treatment with the 5-HT(1A) agonist ipsapirone (3 mg/kg) prevented the ethanol-associated reduction in 5-HT neurons. The present investigation examined whether there was a persistent deficit of 5-HT-immunopositive neurons in the dorsal and median raphe of the offspring of ethanol-fed dams. We also evaluated whether a lower ipsapirone dose (1 mg/kg) was protective to developing 5-HT neurons in the offspring of ethanol-fed dams. The offspring of ethanol-fed dams exhibited an apparent lasting reduction in the density of 5-HT neurons in the dorsal and median raphe. The density of 5-HT neurons in control offspring was comparable at PN5 and PN19, but at both ages the offspring of ethanol-fed dams had a significant deficit of 5-HT neurons in the dorsal and median raphe. The lack of recovery in the density of 5-HT-immunopositive neurons in the offspring of ethanol-fed dams between PN5 and PN19 suggests and that the reduction was long lasting. The protective effects of ipsapirone appeared to be dose dependent. The density of 5-HT neurons in the dorsal and median raphe of PN5 (prior study) and PN19 offspring of ethanol-fed dams that were treated with 3 mg/kg of ipsapirone between gestational day 13 (G13) and G20 was comparable to that of control offspring. However, the effects of maternal treatment of ethanol-fed dams with the 1 mg/kg dose were variable, and some abnormalities were detected in the offspring of ipsapirone-treated control dams.

Animals↗

PubMed2001

Potential involvement of S100B in the protective effects of a serotonin-1a agonist on ethanol-treated astrocytes.

Previously, this laboratory found that the offspring of rats that consumed ethanol on a chronic basis prior to parturition exhibited a significant reduction in serotonin (5-HT) neurons and in astrocytes proximal to these neurons. This laboratory also showed that maternal treatment with a 5-HT(1A) agonist during the latter part of gestation prevented the reduction of 5-HT neurons and most of the astrocyte abnormalities. The present in vitro studies extended our prior in vivo work by examining the potential involvement of S100B with the protective effects of a 5-HT(1A) agonist, i.e., buspirone, on astrocytes. Astrocyte cultures were either maintained in chemically defined media in the presence and absence of ethanol and buspirone or in conditioned media that was generated by ethanol- and buspirone-treated astrocytes. A mouse monoclonal antibody to S100B was used to assess the potential involvement of S100B with the protective effects of buspirone. Additional in vitro studies measured the direct effects of S100B and ethanol on astrocyte proliferation. These investigations demonstrate that in vitro ethanol exposure reduces the number of astrocytes, and that treatment with the 5-HT(1A) agonist buspirone prevents the ethanol-associated reduction in astrocyte number. The protective effects of buspirone appear to be mediated by factors that are secreted by astrocytes; such factors likely include S100B. In addition, added S100B prevents an ethanol-associated reduction in [(3)H]-thymidine incorporation into proliferating astrocytes.

Animals↗

PubMed2000

Effects of in utero ethanol exposure and maternal treatment with a 5-HT(1A) agonist on S100B-containing glial cells.

This laboratory previously showed that in utero ethanol exposure severely impairs the development of the cell bodies and projections of serotonin (5-HT) neurons, and that maternal treatment with a 5-HT(1A) agonist prevents many of these abnormalities. Others demonstrated that stimulation of fetal astroglial 5-HT(1A) receptors increases production and release of S100B, a glial trophic factor that is essential for the development of 5-HT neurons. The present study investigated a potential mechanism by which ethanol hinders development of 5-HT neurons, and by which maternal 5-HT(1A) agonist treatment prevents this damage. This study tested the hypothesis that in utero ethanol exposure reduces the number of S100B immunopositive glia and that maternal 5-HT(1A) agonist treatment prevents ethanol-associated changes in S100B. To test our hypothesis, we determined the effects of in utero ethanol exposure and maternal treatments with the 5-HT(1A) agonists ipsapirone and buspirone on S100B immunopositive glial cells. On gestation day 20 (G20), S100B immunopositive cells were quantified in the midline raphe glial structure (MRGS), a large transient structure that contains substantial numbers of S100B-positive glial cells and that spans the dorsal raphe, median raphe, and B9 complex of 5-HT neurons. S100B immunopositive glial cells were also determined in an area proximal to the dorsal raphe in postnatal day 2 (PN2) rats. In utero ethanol exposure significantly reduced S100B immunopositive glial cells in the MRGS at G20 and in the dorsal raphe at PN2. In addition, treatment of pregnant rats with a 5-HT(1A) agonist between G13 and G20 prevented the ethanol-associated reduction in S100B immunopositive glial cells. These studies demonstrated that part of ethanol's damaging effects on developing 5-HT neurons is mediated by a reduction of S100B and that some of the protective effects of maternal 5-HT(1A) agonist treatment are related to the actions of these drugs on glial cells.

Animals↗

PubMed1999

In utero ethanol exposure decreased the density of serotonin neurons. Maternal ipsapirone treatment exerted a protective effect.

Prior studies from this laboratory showed that in utero ethanol exposure severely retards the development of the serotonin (5-HT) system; we demonstrated a reduced concentration of 5-HT and 5-HT reuptake sites and alterations in the concentration of 5-HT(1A) receptors in ethanol-exposed offspring. These investigations also found that maternal treatment with a 5-HT(1A) agonist, buspirone, prevented most of the ethanol-associated damage to the developing 5-HT system. In the present investigation, we investigated whether the ethanol-associated changes in the 5-HT system are due to a reduction of 5-HT neurons and whether any changes in the density of 5-HT neurons can be prevented by maternal treatment with another 5-HT(1A) agonist, ipsapirone. Using immunocytochemistry, we found that in utero ethanol exposure reduced the density of 5-HT immunopositive neurons in the dorsal raphe, median raphe and B9 neurons of postnatal day 5 (PN5) rats. In all three brain areas, the offspring of ethanol-fed, saline-treated dams exhibited a 28%-40% reduction in 5-HT neurons. Ipsapirone prevented the ethanol-induced reduction in 5-HT immunopositive neurons in the dorsal raphe, median raphe and B9 neurons. In the dorsal and median raphe of control offspring, ipsapirone did not alter the concentration of 5-HT neurons. However, this drug did reduce 5-HT neurons in the B9 region of the offspring of control-fed rats.

Animals↗

PubMed1999

In utero ethanol exposure increases proenkephalin, a precursor of a neuropeptide that is inhibitory to neuronal growth.

BACKGROUND: One of the effects of fetal alcohol syndrome (FAS) is altered motor function. In an attempt to elucidate a potential cause of this ethanol-associated damage, we investigated the effects of in utero ethanol exposure on the production of proenkephalin (PE). METHODS: PE is the precursor of met- and leu-enkephalin, two neuropeptides that inhibit the proliferation of neurons and astrocytes. PE mRNA and PE peptide were measured in the striatum and nucleus accumbens because of the importance of these brain regions to motor function, their sensitivity to the effects of in utero ethanol exposure, and their high concentration of PE mRNA and PE peptide. RESULTS: The present studies demonstrated that in utero ethanol exposure is associated with increased PE mRNA in the striatum and nucleus accumbens. Of specific interest is the elevation in PE mRNA in the nucleus accumbens in 5-, 12-, and 19-day-old ethanol-exposed offspring and the fact that this change persists for at least 19 days after the last exposure to ethanol. Further studies of postnatal day 19 (PN19) offspring localized the abnormality in the nucleus accumbens to the core region, an area that contains enkephalinergic projections to another motor area-the substantia nigra. In the nucleus accumbens, the increased PE mRNA was associated with a greater proportion of PE-expressing neurons that have 41% to 60% of the cell area covered by grains associated with PE mRNA. CONCLUSIONS: Although we were not able to detect a change in the concentration of the PE peptide in the nucleus accumbens or striatum, we cannot rule out the possibility that the increase in PE mRNA was reflective of a functional abnormality.

Animals↗

PubMed1998

Effects of chronic ethanol consumption and aging on proenkephalin and neurotensin.

We examined the combined effects of chronic ethanol consumption and aging on mRNA and peptide for proenkephalin (PE), the precursor of met- and leu-enkephalin. This study also evaluated the effects of aging and alcohol on the level of the mRNA encoding the common precursor of neurotensin (NT) and neuromedin N (NN). PE mRNA and NT/NN mRNA were quantitated in multiple brain areas of 5- and 24-month-old male Fischer 344 rats. Aging, but not chronic ethanol consumption, altered PE mRNA and peptide levels. Aging was accompanied by a loss of PE peptide and PE mRNA in the rostral striatum. In aged rats, PE mRNA was also reduced in the shell region of the nucleus accumbens. The decline in PE mRNA in the rostral striatum and shell region of the nucleus accumbens was caused by a reduction in the number of cells that contain PE mRNA. The percentage of PE mRNA-containing neurons that express a high amount of PE mRNA was also lower in the rostral striatum of 24-month-old rats. The effects of aging may impair motor function and alter the rewarding properties of ethanol consumption. Neither aging nor alcohol changed the PE mRNA levels in the core region of the nucleus accumbens, the frontal cortex, and the piriform cortex. In contrast to PE mRNA, neither aging nor chronic ethanol consumption affected NT/NN mRNA in the regions analyzed. Normal NT/NN mRNA levels were found in the lateral septum and two hippocampal brain areas: the dorsal subiculum and CA1 regions.

Age Factors↗

PubMed1997

Effects of maternal ethanol consumption and buspirone treatment on dopamine and norepinephrine reuptake sites and D1 receptors in offspring.

Previously, it was shown that in utero ethanol exposure results in decreased serotonin (5-HT) and altered concentrations of 5-HT reuptake sites and 5-HT1A receptors in fetal and/or postnatal rats. Because fetal 5-HT is an essential trophic factor, this laboratory previously investigated the hypotheses that the early ethanol-associated 5-HT deficit contributed to subsequent development abnormalities in the serotonergic system and that the effects of the fetal 5-HT deficit could be prevented by maternal treatment with buspirone, a 5-HT1A receptor agonist. The present report determined the effects of maternal treatment with buspirone on two other neurotransmitter systems in the developing offspring of ethanol-fed dams: dopamine (DA) and norepinephrine reuptake sites and D1 receptors in postnatal day 19 offspring of control and ethanol-fed dams, that received daily injections of saline or 4.5 mg/kg buspirone. These investigations found that in utero ethanol exposure significantly decreased norepinephrine reuptake sites in the dorsomedial hypothalamic nucleus and anteroventral thalamic nucleus. There was also an ethanol effect in the dorsal raphe. D1 receptors were moderately increased (5-10% increase) in the striatum, and DA reuptake sites were unchanged in PN19 ethanol-exposed offspring. No other significant ethanol-related effects were noted. Maternal buspirone treatment did not adversely affect the concentration of DA reuptake sites or D1 receptors in control rats. Thus, whereas buspirone exerts protective effects on the developing 5-HT system of ethanol-exposed rats, it does not appear to damage the development of the DA system. Maternal buspirone produced only one significant abnormality in control offspring; it resulted in significant reduction of norepinephrine reuptake sites in the DR.

Animals↗

PubMed1997

Effects of chronic ethanol consumption and aging on 5-HT2A receptors and 5-HT reuptake sites.

The serotonergic system in brain is adversely affected by both aging and chronic ethanol consumption. The present study examined the combined effects of aging and chronic ethanol consumption on two components of the serotonergic system. Serotonin (5-HT) reuptake sites and 5-HT2A receptors were quantitated in brain areas of 5-, 14-, and 24-month-old male Fischer 344 rats that were pair-fed a control or 6.6% (v/v) ethanol-containing liquid diet on a chronic basis. The regions examined include those containing the cell bodies and projections of serotonergic neurons. These experiments demonstrated the sensitivity of the serotonergic system of male Fischer 344 rats to both aging and chronic ethanol consumption. In control rats, aging was associated with a decline in the concentration of 5-HT2A receptors in the nucleus accumbens and four cortical regions: frontal, parietal, piriform, and cingulate cortex. 5-HT2A receptors were also reduced in the frontal, parietal, and cingulate cortex of aged ethanol-fed rats. In contrast, 5-HT reuptake sites were increased in older rats in the frontal cortex, nucleus accumbens, amygdala, and CA3 region of the hippocampus. If comparable changes in 5-HT2A receptors and 5-HT reuptake sites occur in elderly humans, they may contribute to ethanol consumption, and lead to cognitive and other age-related problems. These changes may also alter the effectiveness of serotonergic drugs used in the treatment of alcoholism and mental disorders. The effects of chronic ethanol consumption were more limited. The only significant ethanol effect was an increase of 5-HT2A receptors in the nucleus accumbens of 5-month-old ethanol-fed rats.

Age Factors↗

PubMed1997

Effects of maternal ethanol consumption and buspirone treatment on 5-HT1A and 5-HT2A receptors in offspring.

In utero ethanol exposure results in a decreased concentration of serotonin (5-HT) in brain regions containing the cell bodies of 5-HT neurons and their cortical projections. The concentration of 5-HT reuptake sites is also reduced in several brain areas. The present study extended prior work by evaluating the effects of chronic maternal ethanol consumption and maternal buspirone treatment on 5-HT1A and 5-HT2A receptors in multiple brain areas of offspring. Receptors were quantitated early in postnatal development and at an age when the 5-HT networks are normally well-established. Because fetal 5-HT functions as an essential neurotrophic factor, these studies also determined whether treatment of pregnant rats with buspirone, a 5-HT1A agonist, could overcome the effects of the fetal 5-HT deficit and prevent ethanol-associated receptor abnormalities. The results demonstrated that in utero ethanol exposure significantly alters the binding of 0.1 nM [3H]-8-hydroxy-dipropylaminotetralin to 5-HT1A receptors in developing animals. Ethanol impaired the development of 5-HT1A receptors in the frontal cortex, parietal cortex, and lateral septum; these receptors did not undergo the normal developmental increase between postnatal days 19 and 35. The dentate gyrus was also sensitive to the effects of in utero ethanol exposure. 5-HT1A receptors were increased in this region at 19 days. Maternal buspirone treatment prevented the ethanol-associated abnormalities in 5-HT1A receptors in the dentate gyrus, frontal cortex, and lateral septum. Neither maternal ethanol consumption nor buspirone treatment altered the binding of 2 nM [3H]ketanserin to 5-HT2A receptors in the ventral dentate gyrus, dorsal raphe, parietal and frontal cortexes, striatum, substantia nigra, or nucleus accumbens.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed1996

Deficiency of essential neurotrophic factors in conditioned media produced by ethanol-exposed cortical astrocytes.

Prior research in this laboratory has shown that in utero ethanol exposure adversely affects the development of serotonergic neurons. The current study investigated the hypothesis that cortical astrocytes produce trophic factors which are essential for the development of the fetal precursors of serotonergic and other raphe neurons (e.g. rhombencephalic neurons), and that ethanol exposure impairs the production of these factors by astrocytes. The results of these experiments demonstrated that cultured cortical astrocytes produce trophic factors which are necessary for the development of rhombencephalic neurons. Conditioned media obtained from control astrocytes promoted both general neuronal development (increased cell number, cell survival, DNA content, protein content, and neurite outgrowth) and serotonergic neuronal development (increased number of serotonin (5-HT) immunopositive cells and [3H]5-HT uptake). However, the conditioned media produced by ethanol-treated astrocytes (ECM) lacked essential neurotrophic factors. Neuronal cultures maintained in ECM had reduced DNA and neuronal survival, and altered neurite outgrowth. 5-HT immunopositive neurons and [3H]5-HT uptake were also decreased in ECM cultures. Thus, the damaging effects of in utero ethanol exposure on developing serotonergic neurons may be due to impaired production of astroglial neurotrophic factors.

Animals↗

PubMed1996

Protective effects of maternal buspirone treatment on serotonin reuptake sites in ethanol-exposed offspring.

Previous work in this laboratory demonstrated that in utero ethanol exposure is associated with abnormal development of the serotonergic system. Specific abnormalities included deficiencies of serotonin (5-HT) and its metabolites, and cortical 5-HT reuptake sites. The concentration of 5-HT1A receptors was also altered. The serotonin deficit was detected in the fetal ethanol-exposed brain, at an age when 5-HT would normally function as an essential trophic factor. Thus, it was hypothesized that the early 5-HT ethanol-associated deficit of an essential trophic factor (e.g. 5-HT) could contribute to subsequent developmental abnormalities in serotonergic neurons. In the present investigation we used quantitative autoradiography (QAR) to more fully characterize the developmental abnormalities in 5-HT reuptake sites in developing offspring of ethanol-fed rats. In addition, we attempted to overcome the potential negative impact of the ethanol-associated deficit of fetal 5-HT, by administering a 5-HT1A agonist, buspirone, to pregnant rats. These investigations demonstrated that postnatal (PN) 19 and/or 35 day ethanol-exposed offspring had a significant decrease in [3H]citalopram binding to 5-HT reuptake sites in the frontal cortex, parietal cortex, lateral hypothalamus, substantia nigra, medial septum, and striatum. In contrast, [3H]citalopram binding was increased in the dorsal raphe on PN5 and in the median raphe on PN19. No significant ethanol-associated changes were detected in the hippocampus CA3 region or in the amygdala. When [3H]citalopram binding was compared in the offspring of saline- and buspirone-treated dams, it appeared that maternal treatment with buspirone prevented or reversed most of the ethanol-associated developmental abnormalities in 5-HT reuptake sites. Buspirone prevented the decline in binding of [3H]citalopram in the frontal cortex, lateral hypothalamus, substantia nigra and medial septum. Similarly, buspirone treatment prevented the ethanol-associated increase in binding in the dorsal and median raphe. Additional experiments are needed to elucidate the impact of maternal buspirone treatment on the development of other neurotransmitter systems in offspring.

Animals↗

PubMed1996

Effects of chronic ethanol consumption and aging on dopamine, serotonin, and metabolites.

This study examined the hypothesis that chronic ethanol consumption results in significant abnormalities in both the dopaminergic and the serotonergic system of aged rats. Levels of dopamine (DA), serotonin [5-hydroxytryptamine (5-HT)], 3,4-dihydroxyphenylacetic acid (DOPAC), and 5-hydroxyindole-3-acetic acid (5-HIAA) were determined in brain areas of both the nigrostriatal and mesocorticolimbic DA systems in 5-, 14-, and 24-month-old male Fischer 344 rats. Aging was associated with a reduced concentration of DA in the striatum (ST), ventral tegmental area (VTA), and ventral pallidum (VP) and an increased concentration of 5-HIAA in the ST, globus pallidus, nucleus accumbens, frontal cortex, and VP. In addition, there was an increase in the 5-HIAA/5-HT ratio in all brain areas analyzed. Six weeks of ethanol consumption was accompanied by significant changes in mesocorticolimbic brain areas. In the VTA of 5-month-old ethanol-fed rats DA content was decreased to the levels found in aged rats, e.g., 24 months of age. Ethanol also significantly lowered 5-HT and 5-HIAA contents in the VTA and reduced DOPAC and 5-HIAA levels in the VP. In addition, ethanol blunted the normal age-related increase in 5-HIAA/5-HT ratio in the VTA, VP, and substantia nigra. It is interesting that although the age-related changes were found in both nigrostriatal and mesocorticolimbic brain areas, the ethanol-associated effects were found only in brain areas of the mesocorticolimbic system. The changes in DA and 5-HT function that accompany aging and ethanol consumption may contribute to the problems in motor function and ethanol abuse found in the aged.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1996

Effects of chronic alcohol consumption and aging on dopamine D2 receptors in Fischer 344 rats.

Aging and chronic alcohol consumption are each accompanied by significant changes in dopamine and dopamine receptors. This study extended previous work by investigating the combined effects of chronic alcoholism and aging on total dopamine D2 receptors in brain areas associated with the nigrostriatal and mesocorticolimbic systems. In addition, the effects of chronic alcohol consumption and aging on the high-affinity state of D2 receptors and their conversion to the low-affinity form is included. Quantitative autoradiography was used to assess [3H]spiperone-labeled D2 receptors in tissue sections from 5- to 14- and 24-month Fischer 344 rats that were pair-fed a control or 6.6% (v/v) ethanol-containing liquid diet for 6 weeks. In addition, D2 receptors were determined in rats given the control liquid diet ad libitum. The results of these experiments demonstrated age-related changes in the nigrostriatal system. There was an age-related loss of total dopamine D2 receptors in the rostral and caudal striatum (approximately 25% decrease in Bmax). This decline in D2 receptors may be associated with changes in motor function. Despite the age-related decline in D2 receptors, there were no significant differences in the proportion of striatal receptors in the high-affinity form or in their conversion to the low-affinity state. Both aging and chronic alcohol consumption produced significant changes in the concentration of D2 receptors in brain areas associated with the mesocorticolimbic system. That is, the specific binding of [3H]spiperone was decreased in the frontal cortex of aged rats. In addition, chronic alcoholism was associated with a significant increase (approximately 20%) in the Bmax for D2 receptors in the nucleus accumbens. Nonetheless, neither age nor chronic alcohol consumption altered the proportion of high-affinity D2 receptors in the nucleus accumbens or their conversion to the lower affinity state. The observed changes in D2 receptors in the frontal cortex and nucleus accumbens are of interest because of the involvement of the mesocorticolimbic dopamine areas in the rewarding properties of alcohol and other drugs of abuse. Although aging and chronic alcoholism both produced significant changes in dopamine D2 receptor concentrations, alcohol did not accentuate the age-related loss of D2 receptors. We cannot eliminate the possibility that a more prolonged exposure of higher ethanol dose may potentiate age-related changes in the dopaminergic system.

Age Factors↗

PubMed1995

Effects of chronic alcohol consumption and aging on dopamine D1 receptors in Fischer 344 rats.

The present study examined the hypothesis that chronic alcoholism augments the age-related loss of dopamine D1 receptors. This hypothesis was investigated because previous studies reported that both aging and chronic alcoholism produce significant changes in dopaminergic systems, and because chronic alcoholism potentiates some age-related CNS losses. In addition, this study investigated the effects of aging on D1 receptors in animals 1 and 7 days after withdrawal from chronic ethanol. Quantitative autoradiography was used to measure [3H]SCH 23390 binding to D1 receptors in brain areas associated with both the nigrostriatal and mesocorticolimbic dopamine systems. Receptors were assessed in 5-, 14-, and 24-month-old male Fischer 344 rats that were pair-fed a control or 6.6% (v/v) ethanol-containing liquid diet for 6 weeks. The results of these studies demonstrated that aging is associated with a significant decline in D1 receptors in the rostral and caudal striatum, and substantia nigra of both control and ethanol-fed rats. These receptor changes in the nigrostriatal system may be associated with motor abnormalities. In addition, there was an age-related decline in D1 receptors in two brain areas of the mesocorticolimbic system: the nucleus accumbens and frontal cortex. The latter findings may be important because of the involvement of this system with the rewarding properties of ethanol and other drugs of abuse. There were no age-related differences in the response of D1 receptors to ethanol withdrawal in the caudal and rostral striatum, substantia nigra, and nucleus accumbens.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1994

Maternal ethanol consumption: effects on G proteins and second messengers in brain regions of offspring.

Previous work in this and other laboratories has demonstrated that in utero ethanol exposure adversely affects the development of the serotonergic, dopaminergic, cholinergic, and other neurotransmitter systems. In several of these systems, receptor number is significantly altered. To determine whether the altered number of two G protein-linked receptors is reflected in changes in cell function, we examined dopamine-stimulated adenylate cyclase in the striatum and cortex and carbachol-stimulated phosphoinositide (PI) hydrolysis in the cortex. Serotonin-stimulated cortical PI hydrolysis was assessed for comparison. We also studied G proteins that link adenylate cyclase and other second messenger systems to their receptors. The G proteins that were analyzed include the alpha-subunits for Gs, G0, Gi1, Gi2, and Gi3. G proteins were analyzed in the cortex and cortical regions, as well as in the brain stem. The results of these experiments demonstrated that dopamine-stimulated adenylate cyclase activity was comparable in the striatum of 5- and 19-day offspring of control and ethanol-fed rats and in the motor cortex of 19-day offspring. We also found that carbachol- and serotonin-stimulated hydrolysis of cortical phosphoinositides was unchanged in ethanol-exposed offspring on gestational day 19, and on postnatal days 5 and 19. G protein content was examined by Western blot analysis, using antibodies directed against the alpha-subunits of Gs, G0, and the Gi1/Gi2 and Gi3/G0 combinations. These investigations indicated that, with two minor exceptions (approximately 10% change in the proteins detected by antibodies against the alpha-subunits of the Gi1/Gi2 and Gi3/G0 combinations), there were no significant differences in the content of any of the G proteins analyzed.

Acetylcholine↗

PubMed1993

Effects of ethanol on cultured fetal serotonergic neurons.

In utero ethanol exposure impairs the development of several neurotransmitter systems, including the serotonergic system. However, at present the mechanism by which in utero ethanol exposure damages the developing brain is unknown. This research examined the possibility that ethanol directly impairs the development of serotonergic neurons. This hypothesis was assessed by examining the content of serotonin (5-HT), 5-HT uptake, and 5-HT immunopositive neurons in cultures of fetal rhombencephalic neurons that were exposed to ethanol for 4 days in vitro. In addition, the effects of in vitro ethanol exposure on protein and DNA content of cultured rhombencephalic neurons were determined. These studies demonstrated that a 4-day exposure of cultured rhombencephalic neurons to 50 to 300 mg ethanol/dl did not affect 5-HT content, 5-HT uptake, or the proportion of 5-HT immunopositive neurons. In addition, this ethanol exposure had no significant effect on protein or DNA content. Additional studies, using a 4-day exposure to 450 mg ethanol/dl also did not detect significant differences in 5-HT uptake or in protein or DNA content. The marked differences in the findings of the present in vitro and previous in vivo studies may be due to the fact that the ethanol exposure in vivo was longer than that in vitro, and included the period of early development of serotonergic neurons and their progenitors. Alternatively, the differences may be due to ethanol-associated alterations in maternal or fetal factors (e.g., hormones, amino acids, and growth factors) that are necessary for the normal development of the serotonergic system in vivo. Normal concentrations of such factors in the serum-containing media may have protected the cultured neurons from the damaging effects of ethanol.

Animals↗

PubMed1993

Treatment of pregnant alcohol-consuming rats with buspirone: effects on serotonin and 5-hydroxyindoleacetic acid content in offspring.

This laboratory previously demonstrated that in utero ethanol exposure markedly impairs the development of the serotonergic system in rat brain. Developmental abnormalities could be detected as early as G15 in the brainstem and G19 in the cortex. Because of the importance of fetal serotonin (5-HT) and 5-HT1A receptors for the normal development of 5-HT containing neurons, we initiated studies to determine whether administration of a 5-HT1A agonist, buspirone, to pregnant rats could overcome the adverse effects of in utero ethanol exposure on the developing serotonergic system in offspring. Female, Sprague-Dawley rats were given daily subcutaneous injections of buspirone (4.5 mg/kg) from gestational day 13 (G13) to G20. 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) content were determined in the cortex and cortical regions. These experiments demonstrated that the ethanol-associated abnormalities in the development of the serotonergic system can be partially overcome by in utero exposure to buspirone. Specifically, whereas untreated ethanol rats had a deficiency of 5-HT and/or 5-HIAA in whole cortex on PN5, and in the motor cortex on PN19 and 35, no significant differences were detected in these regions of the age-matched offspring of buspirone-treated, ethanol-fed rats. In contrast, the 5-HT and 5-HIAA deficiency in the somatosensory cortex of 19-day-old offspring of ethanol-fed rats was not corrected by in utero buspirone treatment. These results suggest that the abnormal development of cortical projections of serotonergic neurons may be due in part to the low fetal 5-HT content in ethanol-exposed rats and may potentially be overcome by in utero treatment with a 5-HT1A agonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗