Biomedical subjects

K F Soliman

Publications and source records attributed to K F Soliman.

At least 37 records · Page 2Linked to original sources

PubMed1997

The effect of selenium on the central dopaminergic system: a microdialysis study.

The effects of Selenium (Se) on central dopaminergic function were examined in male Sprague-Dawley rats. In this experiment, animals were implanted with microdialysis probes and dialysates were analyzed for dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). After reaching baseline values, sodium selenite was either injected intraperitoneally (i.p.) or directly infused into the striatum (ST) or nucleus accumbens (NA). Se administration of 3.0 mg/kg (i.p.) significantly increased (70%) DA overflow in the ST. Meanwhile direct Se perfusion (10 mM) also caused a significant elevation of synaptic DA concentrations in the ST and NA. Levels of DOPAC and HVA were minimally affected in all studies. In order to test for the effects of DA receptor activation, animals were pretreated with quinpirole (0.5 mg/kg, s.c.), an hour prior to Se (10 mM) infusion through the probe. It was found that quinpirole pre-treatment reduced Se-induced changes in DA concentrations. It was concluded from the present study that Se's central action might be related to its ability to potentiate DA function.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1997

In vivo response of the normal and regenerating adrenal glands to thyroid manipulation in rats.

Adrenal corticosterone (CORT) levels and ornithine decarboxylase (ODC) activities in thyroid intact, thyroidectomized, and thyroxine (2 micrograms/ml in drinking water for 3 weeks) supplemented rats were measured 11 days after adrenal sham surgery or enucleation. Thyroidectomy decreased and thyroxine supplementation increased adrenal CORT significantly (p < 0.05) at 0600 h and 1800 h. The ODC activity was not significantly affected by thyroidectomy. Thyroxine supplementation however, inhibited ODC activity significantly (p < 0.05) at 1800 h in the regenerating adrenal cortex. Results indicated that, while CORT response in normal and regenerating adrenals are positively related to thyroid manipulation, inhibition of adrenal ODC activity by thyroxine may affect adrenal regeneration.

Adrenal Glands↗

PubMed1997

Behavioral and neurochemical effects of acute and repeated administration of triadimefon in the male rat.

The effects of triadimefon (TDF) were examined in male Sprague-Dawley rats. In this study, the acute administration of TDF (100 mg/kg) was found to significantly increase locomotor activity and induce stereotyped behavior. Acute administration of TDF was also found to significantly increase dopamine (DA) and homovanillic acid (HVA) levels while the dihydroxyphenylacetic acid (DOPAC) level remained unchanged in both the nucleus accumbens (NA) and striatal (ST) tissues when compared to control. Furthermore, DOPAC:DA ratios were significantly reduced in both brain regions suggesting an increase in DA turn overrate. On the other hand, in animals receiving repeated TDF administration, only the HVA level was significantly increased in both the ST and NA. TDF neither competed for binding to D2, D3 or D4 DA receptors nor altered the Kd or the Bmax of [3H] SCH 23390 and [3H] spiperone recognition sites associated with striatal D1 and D2 receptors, respectively. Meanwhile, TDF competed with [3H] GBR 12935 for binding to DA transporter sites with strong affinity, but repeated treatment with TDF had no sustained or cumulative effect on the DA transporter system. These results clearly show that acute TDF-induced behavioral effects may not be via binding to DA receptors, but through the interaction with DA transporter binding sites. Also, TDF does not appear to produce cumulative effects in the parameters evaluated.

Animals↗

PubMed1996

Decreased endurance to cold water swimming and delayed sexual maturity in the rat following neonatal lead exposure.

The effects of neonatal lead (Pb) exposure on ability to endure stress and on the onset of sexual maturity were investigated using rats. Sprague-Dawley dams (n = 17/treatment) were treated with or without lead acetate (0.3%) in drinking water from parturition until postnatal day (PND) 21, at which time the pups were weaned. A set of sex-balanced pairs of pups (24 male and 24 females/treatment) from randomly selected control and Pb-treated dams was tested for cold water (4 degrees C) swimming-endurance on PND 15, 21, 25 and 30. Lead treated-female pups showed significantly (P < 0.05) lower endurance on PND 21 and 30, while Pb-treated males exhibited lower (P < 0.05) endurance on PND 21 compared to their respective controls. The results of this study indicate that neonatal exposure to Pb decreased cold water swimming-endurance. Neonatal exposure to either Pb or swimming stress delayed (P < 0.002) the onset of sexual maturity in both sexes. However, exposure to both treatments masked the effect of swimming stress on the onset of maturity in females but not in males.

Analysis of Variance↗

PubMed1994

Single gene effect on alcohol preference in the Zucker rats.

Zucker obese (ZO), Zucker lean (ZL), and Sprague-Dawley (SD) naive rats of both sexes were used to study the role of the fa/fa gene on alcohol preference. During the first two weeks of this experiment (weeks 1-2) all rats received a 10% alcohol solution ad lib as the only source of liquid. Animals were then given free access to both water and alcohol for the following three weeks (weeks 3-5). Thereafter, rats were deprived of alcohol every other day for two weeks (weeks 6-7), then completely deprived of alcohol for one week (week 8). Finally, unlimited access to both water and alcohol solution was available for the last two weeks of the experiment (weeks 9-10). Results of this study show that when rats were offered both water and alcohol (weeks 3-5), ZL rats consumed significantly more alcohol (2.5-fold) than their littermates, the ZO rats and the SD rats. Similarly, during alternate days of alcohol deprivation (weeks 6-7), ZL rats consumed significantly more alcohol (threefold) than the ZO rats and the SD rats. After a week of alcohol deprivation (week 8), and during the final two weeks (weeks 9 and 10), ZL rats continued to consume significantly more alcohol (2.5-fold) than the ZO group or the SD group. ZL females consumed more alcohol per kg body weight than male ZL rats. Data obtained from this study suggest that in the Zucker rat a single gene can alter the animal alcohol preference.

Alcohol Drinking↗

PubMed1994

Serotonin modulation of pain responsiveness in the aged rat.

This study was designed to examine differences in basal nociceptive responsiveness between young (3 months) and old (25 months) male Fischer-344 rats and also to evaluate the effects of methysergide and fluoxetine on this behavioral paradigm. The results indicate that the aged animals were less sensitive than young animals to pain responsiveness in simple nociceptive tests such as the tail-flick, hot plate (55 degrees C), and hind-paw pressure tests. In both groups of animals, this behavioral response followed a circadian rhythm, with peak of pain latency during the dark phase and trough occurring in the light phase. In all three analgesic tests, treatment with methysergide, which is a serotonin antagonist, resulted in hyperalgesia in both groups of animals within the first hour, followed by a return to basal response level after 2 h. Fluoxetine treatment resulted in a nonsignificant increase in nociceptive response at 30 min posttreatment which returned to the baseline by 1 h. Moreover, in both young and old animals morphine produced moderate analgesia in the hot plate and hind-paw tests, which was potentiated by simultaneous treatment with fluoxetine. This study shows that noxious response was reduced in the aged male Fischer-344 rats, and the data obtained provide evidence that the serotonergic system modulates pain sensitivity similarly in young and old animals.

Aging↗

PubMed1993

Biochemical evidence for peripheral neural regulation of adrenocortical regeneration in response to bilateral adrenal enucleation.

Male Sprague-Dawley rats (130-150 g) with bilateral adrenal enucleation were used in this study. Animals were sacrificed at 2, 7, and 11 days post enucleation and plasma corticosterone and adrenal gland acetylcholine-esterase (AChE), choline acetyltransferase (ChAT), corticosterone, epinephrine (EP) and norepinephrine (NE) were assayed. The results show a progressive and gradual increase in plasma and adrenal corticosterone levels, AChE, ChAT, EP, and NE levels in the regenerating adrenal cortex from day 2 to day 11 post bilateral adrenal enucleation. At day 11 post surgery, the activities of ChAT and AChE were 60% and 25%, respectively when compared to sham operated control. The EP and NE levels returned to normal levels after 11 days post surgery in the regenerating gland when compared to the sham control. The presence of both cholinergic enzymes and the availability of high levels of catecholamine strongly suggest a progressive development of sympathetic innervation in the regenerating adrenal cortex.

Acetylcholinesterase↗

PubMed1993

Circadian variation in tolerance to the hypothermic action of CNS drugs.

Male SAF mice (30-35 g) or male Sprague-Dawley rats (180-250 g) were used to study the circadian variation in tolerance to the hypothermic action of ethanol, apomorphine, and nicotine. Animals were treated for 2 or 3 consecutive days during the light phase (1000, 1400, or 1800 h) or the dark phase (2200, 0200, or 0600 h) and hypothermia produced measured. In one experiment, repeated injections of 20% ethanol (3 g/kg, IP) to mice resulted in varying degrees of hypothermia depending upon the time of injection. Tolerance to hypothermic action was observed only in animals treated during the light phase. On the contrary, the hypothermic response in animals treated during the dark phase increased. In another experiment, apomorphine (15 mg/kg, IP) was used and tolerance to apomorphine-induced hypothermia observed following repeated injections during the light phase with maximum tolerance noticed at 1400 h. In the third experiment, nicotine (2 mg/kg, IP) was repeatedly administered and resulted in tolerance development when given during the light phase. These results indicate that the rapid development of tolerance to CNS drugs studied is a diurnally controlled phenomenon.

Animals↗

PubMed1992

Effect of stress on choline acetyltransferase activity of the brain and the adrenal of the rat.

Choline acetyltransferase (ChAT) activity was determined in cerebral cortex, hypothalamus, hippocampus, cerebellum, medulla oblongata, midbrain and adrenal gland of rats exposed to acute or chronic stress. The exposure of animals to acute immobilization and cold stress (4 degrees C) for one hour resulted in a significant decline of ChAT activity in all brain regions examined except for the medulla oblongata. Moreover, the exposure to acute stress resulted in significant increase of the same enzyme in the adrenal gland. However, chronic exposure of animals to cold stress (4 degrees C) for 7 days resulted in no significant changes of ChAT activity in all tissues examined except for a decline in the midbrain and an increase in the medulla oblongata. The administration of corticosterone (2.0 mg/kg) 1 h prior to sacrificing caused an effect similar to that of acute stress on ChAT activity in all brain regions except for the hypothalamus and the cerebellum. It was concluded from this experiment that stress-induced changes in the ChAT activity of specific brain regions might be mediated by the adrenal steroids.

Adrenal Glands↗

PubMed1992

Effect of diabetes on the cholinergic enzyme activities of the urinary bladder and the seminal vesicles of the rat.

Choline acetyltransferase (ChAT) and acetyl-cholinesterase (AChE) activities were determined in the seminal vesicles and in two regions of the urinary bladder, the detrusor muscle and sphincter-trigon in control and streptozotocin(STZ)-induced diabetic male Sprague-Dawley rats. In this study, STZ was administered (65 mg/kg, i.p.) to induce diabetes 14 days prior to sacrifice and enzyme analysis. Diabetic rats exhibited significant increase in both ChAT and AChE activities in the detrusor compared to the control animals. Significant increases in ChAT activity, however, were observed only in the seminal vesicles of diabetic animals compared to the control group. AChE activity in the seminal vesicles and sphincter-trigon region of the diabetic rats was not altered significantly. These findings suggest that urogenital complications associated with diabetes may be related to the dysfunction of the peripheral cholinergic system.

Acetylcholinesterase↗

PubMed1991

Altered brain cholinergic enzymes activity in the genetically obese rat.

Genetically obese male Zucker rats (fa/fa) and their lean littermates (Fa/-) were used in this experiment. Fourteen-week-old obese and lean littermates were sacrificed and choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) enzymes were assayed in specific brain regions. The assays of these enzymes indicate that obese animals had a significantly lower ChAT activity in the cerebellum, pons, and cerebral cortex and a significant increase in ChAT activity in the thalamus and hypothalamus. Meanwhile, the cerebral cortex, cerebellum, midbrain, thalamus and hypothalamus of the obese animals showed significantly higher AChE activity than their lean littermates. It was concluded from this study that obesity may be associated with changes in the enzymes of the brain cholinergic system.

Acetylcholinesterase↗

PubMed1990

Effect of acute cocaine administration on the cholinergic enzyme levels of specific brain regions in the rat.

Adult male Sprague-Dawley rats weighing between 170 and 204 g and maintained under controlled lighting and temperature conditions were used in this experiment. One group of animals was treated with 30 mg/kg of cocaine hydrochloride and the other group with saline. Rats were decapitated 20 min after cocaine injection and their brains were removed and the different regions including the medulla, pons, midbrain, cerebellum, hypothalamus, thalamus, hippocampus, and the cortex were dissected. All brain regions were assayed for choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities. The results obtained indicated that the administration of cocaine was associated with significant increases (p less than 0.01) in AChE activity in the medulla, pons, midbrain, hypothalamus, thalamus, and also in the hippocampus (p less than 0.05). A significant decrease in ChAT activity was found in the pons (p less than 0.01), hypothalamus, and thalamus (p less than 0.05), while a significant increase in ChAT activity was found in the cortex (p less than 0.05). The results suggest that the changes in general activity followed by stereotypic behavior may be related to the changes in the levels of cholinergic enzymes in specific brain regions.

Acetylcholinesterase↗

PubMed1989

Influence of ethanol on fetal brain cholinergic enzyme activities.

Cultured brain cells from rat fetuses of ethanol-treated mothers demonstrated more than 2-fold elevations in choline acetyltransferase (ChAT) activity relative to those of control (saline-exposed) fetal brain cells. When cells from control animals were incubated in vitro for 5 days with 0.1% ethanol, ChAT activity was found to increase more than 4-fold. Brain cells from in utero ethanol-treated animals further exposed to ethanol in vitro for 5 days demonstrated significantly higher ChAT activity compared to cells exposed to ethanol only in vivo. These levels were more than 6 times greater than those of central nervous system cells never exposed to ethanol. Acetylcholinesterase (AChE) activity was significantly elevated (greater than 4-fold) in fetal brain cells when ethanol was present both in vivo and in vitro, but neither treatment alone resulted in any significant changes in AChE. These effects of ethanol on enzymes involved in acetylcholine metabolism may contribute to the different developmental neurologic abnormalities associated with fetal alcohol exposure.

Acetylcholinesterase↗

PubMed1988

Corticosteroid effects on cholinergic enzymes in ethanol-treated fetal brain cell cultures.

In the presence of ethanol, corticosterone and dexamethasone inhibit choline acetyltransferase and acetyl-cholinesterase activities in cultured fetal brain cells of the rat. These results suggest that corticosteroids may have an important influence on the activity of cholinergic enzymes in the fetal brain may antagonize the effects of ethanol in this setting.

Acetylcholinesterase↗

PubMed1988

Effect of diabetes on the enzymes of the cholinergic system of the rat brain.

Choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities were determined in several brain regions of normal and streptozotocin-induced diabetic rats. The diabetic rats exhibited significant increase in ChAT activity (p less than 0.05) in all brain regions studied except for the cortex and the midbrain. Meanwhile, the diabetes condition was associated with significant increase (p less than 0.05) in AChE activity of the bulbus olfactorius, medulla oblongata and cerebellum. These data suggest that uncontrolled diabetes is associated with significant alterations in the brain cholinergic systems.

Acetylcholinesterase↗

PubMed1988

Hyperglycemic suppression of morphine withdrawal signs in the rat.

Male Sprague-Dawley rats maintained under controlled lighting and temperature conditions were used in this experiment. Morphine dependency was induced by giving increasing doses of morphine by intraperitoneal injection (IP group) or by the ingestion of morphine through drinking water (PO group). Animals were injected with 10, 20, 30 and 50 mg/kg morphine sulfate at days 1, 2, 3 and 4, respectively. Another group of animals received increasing concentrations of morphine through drinking water from 0.1, 0.2, 0.3 to 0.4 mg/ml at 48 h intervals. Morphine dependent animals were given naloxone by the intraperitoneal route to precipitate withdrawal. Glucose (3 g/kg or 10 g/kg) was given 10 min prior to the administration of naloxone to the respective groups. Another two groups of animals were made diabetic by the administration of streptozotocin. In one group, animals received increasing concentrations of 10, 20, 30 and 50 mg/kg morphine sulfate by the IP route at days 1, 2, 3 and 4, while the other group was not treated with morphine but was assessed for withdrawal signs to serve as the control. Withdrawal signs were assessed by observing the presence of diarrhea, tremor, piloerection, hunchbacked posture, teeth chattering, salivation, erection, restless activity, territorial exploring, irritability to handling, vocalization and jumping. Results obtained indicate that glucose administration at 10 g/kg abolished most of the withdrawal signs, and we were unable to induce the same degree of morphine dependency in diabetic animals as compared to the non-diabetic groups. It was concluded from this study that hyperglycemia could suppress morphine withdrawal signs.

Animals↗

PubMed1988

Alterations of fetal brain biogenic amine metabolites by maternal ethanol exposure.

1. Pregnant Sprague-Dawley rats treated chronically with ethanol (3 g/kg daily for the last third of pregnancy) had decreased placental weights at birth (ca 23%). 2. Whole fetal brain levels of HVA and 5-HIAA were similarly decreased 32 and 38%, respectively. 3. MHPG levels were also marginally reduced (i.e. 15% decline). 4. In the presence of a potent type A MAO inhibitor (harmaline, 10 mg/kg maternal weight 2 hr before fetal delivery) co-treatment with ethanol was found to result in a 60% elevation of whole fetal brain norepinephrine levels. 5. Other biogenic amines and metabolites were not altered by ethanol treatment.

Animals↗

PubMed1988

Brain cholinergic involvement in the diurnal variations of the rapid development of tolerance to the hypothermic effect of apomorphine.

Male Sprague-Dawley rats maintained under controlled environmental conditions were used. Choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities were determined in the cerebral cortex, bulbus olfactorius, midbrain, hypothalamus, hippocampus, cerebellum, pons and medulla oblongata of control rats and rats treated with apomorphine (15 mg/kg, i.p.) after a single dose or after a second dose administered 24 h later at 10.00 or 22.00 h. Results of this experiment indicate that the repeated administration of apomorphine at 10.00 h was associated with rapid development of tolerance to the hypothermic action of this drug. A single injection of apomorphine resulted in significant (p less than 0.01) decrease of AChE and significant increase of ChAT activity (p less than 0.01) in the cortex, hypothalamus and pons. There were no significant differences between tolerant and control animals in the activities of AChE or ChAT in the bulbus olfactorius, cerebral cortex, midbrain, pons or medulla. On the other hand, repeated administration of apomorphine at 22.00 h was not associated with tolerance to the hypothermic action of this drug. A single injection of apomorphine at 22.00 h resulted in significant (p less than 0.01) increase in AChE activity of the midbrain, hippocampus, and the medulla oblongata with no significant changes in the cerebral cortex and bulbus olfactorius. There was a significant decline (p less than 0.01) of ChAT activity of the hypothalamus, hippocampus, cerebral cortex and the medulla oblongata (p less than 0.05). Meanwhile, there was a significant (p less than 0.05) increase of ChAT activity of the midbrain with no significant changes in the cerebellum, pons and the bulbus olfactorius.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholinesterase↗