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Biomedical subjects

A Reggiani

Publications and source records attributed to A Reggiani.

At least 73 records · Page 4Linked to original sources
PubMed1986

Opioids and beta-receptors interaction: further studies in cultured cells.

In the present paper a further evidence of a functional link between opioids and beta-receptor system in cultured rat C6 cells is presented. We showed that C6 cell exposure to Desmethylimipramine (DMI) causes expression of opioid receptors and loss of beta-receptors. We now show that C6 cells exposure to DMI causes an increase of intracellular levels of opioid peptides and an increase of aminopeptidase activity. In addition, the presence of the aminopeptidase inhibitor bestatin during cell exposure inhibits DMI-induced beta-receptor loss. These results indicate that cell exposure to DMI causes the full expression of the opioid peptide system. This effect could be related to changes of beta-receptor system.

Aminopeptidases↗
PubMed1986

Activity of ibopamine on central nervous system in mice and rats.

Ibopamine (SB-7505), the 3,4-diisobutyryl ester of N-methyldopamine has proved to be able to induce cardiovascular and renal effects after oral administration which were comparable to those of dopamine injected intravenously. In the present paper ibopamine was investigated on some behavioural, motility and biochemical tests with a view to assaying its possible activity on the central nervous system (CNS). The results obtained show that ibopamine has no significant activity on CNS.

Adenylyl Cyclase Inhibitors↗
PubMed1985

Involvement of monoaminergic and peptidergic components in cathinone-induced analgesia.

Evidence has been obtained suggesting that cathinone-induced analgesia depends upon stimulation of alpha-adrenoceptors, followed by release of opioid peptides and by activation of serotonergic pathways. This hypothesis is supported by the following. (1) Cathinone potentiated morphine analgesia and the whole effect was antagonized by naloxone whereas onto the cathinone potentiation was counteracted by phenoxybenzamine. (2) Bestatin potentiated cathinone-induced analgesia and this effect was sensitive to both naloxone and phenoxybenzamine blockade. (3) The analgesic effect of cathinone + bestatin was further potentiated by the serotonin uptake inhibitor citalopram.

Alkaloids↗
PubMed1985

Pelvic ultrasonography in premenarcheal girls: relation to puberty and sex hormone concentrations.

Real time ultrasonography of the pelvic organs was performed on 114 normal premenarcheal girls aged between 2 years and 13 years 11 months. Values were obtained for total uterine length, anteroposterior diameters of the corpus and cervix, corpus/cervix ratio, and uterine and ovarian volumes and the resultant data were grouped according to age. It was concluded that there is no change in uterine size until approximately 7 years of age. Then the uterus begins to enlarge, both in prepubertal girls, in whom this is an age related function, and in pubertal girls, whose uterine growth is influenced not only by age but also by size and, independently of these two factors, by oestradiol concentrations. The onset of a modification in uterine morphology with a greater enlargement of the corpus than the cervix is also seen at age 7 years. Ovarian maturation begins in the very first years of life and, even in pubertal girls, seems to be influenced by age only and not by hormonal stimuli.

Adolescent↗
PubMed1985

Carcinoembryonic antigen, ferritin, anionic glycoproteins, and their sialic acid content in advanced colorectal cancer.

The efficiency of the combination of four tumor markers in recognizing advanced (recurrent or metastatic) colorectal cancer was evaluated. In 31 normal volunteers and in 31 patients with histologically documented colorectal tumor, we measured serum levels of carcinoembryonic antigen (CEA), ferritin, anionic glycoproteins, and their sialic acid content (SA). CEA, ferritin, anionic glycoproteins and SA mean levels were significantly higher in patients than in normal subjects. Among the four markers CEA was the most sensitive (87.1%) and SA the most specific (100%). By using CEA and SA in combination in 29 out of 31 patients, either marker was abnormally high. Ferritin and anionic glycoproteins did not render additional information. CEA serum levels were elevated in 14 out of 15 patients with liver metastasis, while SA was elevated in six out of 15. CEA maintains its central cole as tumor marker in colorectal cancer; the combined use of CEA and SA may add to precision in detecting patients with advanced colorectal cancer. Anionic glycoproteins and ferritin seem of limited usefulness.

Aged↗
PubMed1984

Effect of bestatin and thiorphan on [Met5]enkephalin-Arg6-Phe7-induced analgesia.

We investigated the effect of bestatin, a specific inhibitor of aminopeptidase and thiorphan, a specific inhibitor of enkephalinase A, on the analgesic effect induced by the intracerebral injection of heptapeptide [Met5]enkephalin-Arg6-Phe7 (MEAP) in cannulated rats. In contrast with the results obtained when [Met5]enkephalin (ME) was used, bestatin clearly potentiated the analgesic effect of MEAP, but thiorphan was totally ineffective. These observations indicate that the predominant inactivating mechanism for MEAP is the action of an aminopeptidase whereas this enzyme seems to be little involved in the catabolism of ME. The existence of two different catabolic pathways for MEAP and ME suggests that MEAP may act not only as a precursor of ME but also as an independent neuromodulator.

Amino Acids, Sulfur↗
PubMed1984

Elastic modulus in young diabetic patients (ultrasound measurements of pulse wave velocity).

Aim of this study is to confirm the validity of non-invasive evaluation with Doppler C.W. in the study of arterial diseases and in the identification of pre-clinical arterial lesions. We studied twenty-eight children suffering from diabetes mellitus, and dependent on insulin and a control group composed of twenty-eight healthy persons. All subjects were studied using the methodology of the transit time for the determination of the elastic modulus of the lower limb arterial wall and results were analysed according to a statistical method. Although the groups were small, an increase in pulse wave velocity was noted in diabetic children and a significative correlation was found between the elastic modulus and duration of diabetes.

Adolescent↗
PubMed1983

Effect of inhibition of neuropeptidases on the pain threshold of mice and rats.

The effect of the inhibition of aminopeptidase and enkephalinase A on the pain threshold of mice and rats was investigated, using bestatin and thiorphan as selective peptidase inhibitors. The results indicate that both enzymes are relevant to the catabolism of enkephalins in vivo; however, their simultaneous activation requires particular conditions. These conclusions are based on the following observations: (1) Only concomitant intracerebral treatment with both inhibitors led to an increase in the threshold of animal pain, whereas, in the presence of exogenous peptides, the concomitant injection of both inhibitors in mice elicited an analgesic response greater than the sum of the effects of each single inhibitor. (2) This response could be seen only after acute trauma; in fact, when the drugs were injected through a plastic cannula, only enkephalinase A inhibition was effective in increasing analgesia induced by exogenous peptides.

Aminopeptidases↗
PubMed1981

Ethanol-induced changes of dopaminergic function in three strains of mice characterized by a different population of opiate receptors.

The effects of ethanol have been studied in three strains of mice (DBA 2J, albino, and C57 BL/6J) having different populations of opiate receptors. Acute ethanol treatment induces a significant increase in striatal dopamine metabolism only in the mouse strains (C57 and albino) that are rich in enkephalinergic receptors upon nigrostriatal dopaminergic fibers. After chronic ethanol, the same strains develop tolerance to striatal dihydroxyphenylacetic acid increase, while the striatal dopaminergic recognition sites become supersensitive. DBA mice, which have lower numbers of enkephalinergic receptors and higher levels of enkephalins in the striatum, fail to show changes in central dopaminergic function after acute or chronic ethanol treatment. Our results indicate the importance of an interaction between ethanol and opiate receptors in determining the neurochemical and behavioral effects of ethanol.

Animals↗
PubMed1980

Acute and chronic ethanol administration on specific 3H-GABA binding in different rat brain areas.

Acute ethanol treatment produces a significant decrease of specific 3H-GABA binding in cerebellum while no changes were detectable in other brain areas. Scatchard analysis shows a decrease in receptor affinity but not in the number of GABA binding sites. On the other hand, chronic administration of ethanol selectively increases specific 3H-GABA binding in the striatum. Kinetic analysis of these data shows that ethanol chronic administration produces a significant increase in the number of GABA binding sites. These data may be useful for the understanding of clinical pictures following acute and chronic ethanol intoxication.

Animals↗
PubMed1980

Ethanol effects on dopaminergic function: modulation by the endogenous opioid system.

Different behavioral and biochemical data suggest that ethanol has different effects on central dopaminergic transmission in rat and mouse. We found that ethanol induces an increase of striatal dopamine turnover which does not persist after chronic drinking. Following chronic ethanol treatment, we observed the development of supersensitivity of the striatal dopamine (DA) recognition sites, in terms of an enhanced affinity. We investigated various experimental models to clarify the existence of an enkephalinergic modulation of ethanol effects on the dopaminergic system. We found that in the rat, a pretreatment with naloxone abolishes the striatal DA turnover increase observed after ethanol. DBA 2J mice, which differ from C57 BL/6J and Swiss Albino, by genetically lacking enkephalinergic modulation on dopaminergic activity in the striatum, do not show any change of DA metabolism after acute ethanol. In the rat retina, where we hypothesized a less operant regulation of dopaminergic activity by enkephalins, tolerance does not develop after chronic drinking to the increase in DA turnover as it did in striatum. Our results confirm the importance of the endogenous opioid system in the regulation of the ethanol induced neurochemical and behavioral effects.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1980

Dopamine metabolism and receptor function after acute and chronic ethanol.

Acute ethanol treatment in rats elicits a selective increase in dihydroxyphenylacetic acid (DOPAC) content in striatum. In contrast, striatal DOPAC concentration does not differ from normal values after chronic ethanol treatment. Chronic administration of ethanol however causes a selective increase of specific [3H]spiroperidol binding and met-enkephalin content in the striatum. Kinetic analysis of [3H]spiroperidol binding data shows that after chronic ethanol treatment there is a significant increase in the affinity constant rather than in the number of binding sites for the ligand. Our results support the hypothesis that dopaminergic mechanisms at both pre- and postsynaptic level may be involved in the mediation of some of the central effects observed after ethanol consumption.

Animals↗