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Biomedical subjects

S C Pandey

Publications and source records attributed to S C Pandey.

At least 55 records · Page 3Linked to original sources
PubMed1991

Similar effects of treatment with desipramine and electroconvulsive shock on 5-hydroxytryptamine1A receptors in rat brain.

The effect of chronic and acute treatment with desipramine (DMI) and electroconvulsive shock (ECS) on 5-hydroxytryptamine1A (5-HT1A) receptors was determined in the cortex and the hippocampus brain regions of rats. We observed that chronic treatment with both DMI and ECS significantly decreased 5-HT1A receptors, as determined by [3H]8-hydroxy-2-(di-n-propylamino)tetralin [( 3H]8-OH-DPAT) binding, in the cortex but not in the hippocampus. Acute treatment with DMI or ECS did not significantly alter the 5-HT1A receptors in the cortex. Neither chronic nor acute treatment influenced KD of [3H]8-OH-DPAT binding in the cortex or hippocampus. These results thus suggest that in contrast to the effects on 5-HT2 receptors, tricyclics as well as ECS produce similar effects on 5-HT1A receptors, suggesting that this site may represent a common site of action for antidepressant treatment.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1991

Effect of antidepressants and neuroleptics on phosphoinositide metabolism in human platelets.

The effect of tricyclic antidepressants (imipramine, desipramine, amitriptyline) and several other antidepressants like iprindole, a monoamine oxidase inhibitor phenelzine, trazodone and mianserin as well as cocaine (a potent inhibitor of norepinephrine uptake), and neuroleptics (haloperidol, thioridazine, chlorpromazine) on [3H]inositol phosphate formation was investigated in human platelets. Basal and thrombin-induced [3H]inositol monophosphate ([3H]IP1), [3H]inositol bisphosphate ([3H]IP2) and [3H]inositol trisphosphate ([3H]IP3) production were measured in [3H]myoinositol-labeled platelets in the presence of lithium chloride and in the presence or absence of test drugs. Desipramine, imipramine, amitriptyline and iprindole inhibited thrombin-stimulated formation of [3H]IP2 and [3H]IP3 in human platelets but had no significant effect on [3H]IP1 formation. In contrast, trazodone, mianserin, cocaine and phenelzine had no effect on inositol phosphate formation in thrombin-stimulated human platelets. The neuroleptics thioridazine and chlorpromazine also decreased thrombin-stimulated [3H]IP2 and [3H]IP3 production but not [3H]IP1 in human platelets, whereas haloperidol had no significant effect. The effect of antidepressants and neuroleptics on the level of [3H]phosphatidylinositol ([3H]PI), [3H]phosphatidylinositol 4-phosphate ([3H]PIP) and [3H]phosphatidylinositol 4,5-bisphosphate ([3H]PIP2) was also determined. All of the drugs tested except phenelzine and thioridazine increased the accumulation of [3H]PI, [3H]PIP and [3H]PIP2. Thioridazine increased levels of [3H]PI but decreased the level of [3H]PIP and [3H]PIP2, whereas phenelzine had no effect on [3H]PI, [3H]PIP and [3H]PIP2 interconversion in human platelets.(ABSTRACT TRUNCATED AT 250 WORDS)

Antidepressive Agents, Tricyclic↗
PubMed1991

Effect of desipramine on inositol phosphate formation and inositol phospholipids in rat brain and human platelets.

To examine the mechanism of action of antidepressant drugs, we studied the effect of desipramine (DMI) in vitro on agonist-stimulated inositol phosphate formation and inositol phospholipids in rat brain and human platelets. We observed that DMI inhibited thrombin-stimulated 3H-inositol bisphosphate (IP2) and 3H-inositol trisphosphate (IP3) but not 3H-inositol monophosphate (IP1) formation in human platelets. DMI also inhibited norepinephrine (NE) and serotonin (5-HT) stimulated 3H-IP1 formation in rat cerebral cortex. DMI increased levels of all three 3H-inositol phospholipids, 3H-phosphatidyl inositol (PI), 3H-PI-4-phosphate (PIP), and 3H-PI 4,5-bisphosphate (PIP2), in both platelets and rat cortex. The decreased formation of inositol phosphates and increased levels of [3H]-PI, [3H]-PIP, and [3H]-PIP2 by DMI appears to be due to the inhibition of the enzyme phospholipase C rather than its effects on receptors. It is thus possible that interaction of tricyclic antidepressant drugs with the PI-signaling system may be related to their mechanism of action.

Animals↗
PubMed1990

Platelet serotonin-2 receptor binding sites in depression and suicide.

In order to examine the role of serotonin-2 (5HT2) receptors in depression and suicide, we determined 5HT2 receptors using 125I-lysergic acid diethylamide (LSD) as the binding ligand in platelets obtained from 20 normal control and 23 drug-free depressed patients. Our results indicate significantly increased 125I-LSD binding sites (Bmax) in the platelets of depressed patients compared with normal control subjects. We also observed that a subgroup of depressed patients with a recent history of suicide attempts or suicidal ideation had significantly higher 5HT2 binding sites as compared with nonsuicidal depressed patients and normal controls. There were no significant differences in the apparent dissociation constant (Kd) values in the platelets of depressed patients compared with normal control subjects. To examine if the baseline 5HT2 receptors are related to either the severity of illness or treatment response, we determined the relationships of the baseline Bmax and Kd with baseline Hamilton Depression Rating Scale (HDRS) and Brief Psychiatric Rating Scale (BPRS) scores and change in scores after treatment. We found no significant correlation between baseline Bmax and Kd with the baseline HDRS or BPRS scores or change in these scores after psychoactive drug treatment. These results thus indicate increased platelet 5HT2 receptors in depression, but much more so in depressed patients with suicidal ideation or attempts.

Adult↗
PubMed1990

Role of photoperiod and temperature in production of the oestrus-inducing pheromone in male wild mice.

Ninety adult males divided in six equal groups were exposed to different photoperiods for 21 days. Exposures included natural light (ca 11 hr), long photoperiod (16L:8D) and short photoperiod (8L:16D). The first three groups received these exposures at room temperature (13-20 degrees C) while the remaining three at raised temperature (36-38 degrees C). Soiled bedding of the above males was introduced in the cages of unisexually housed noncyclic females and their potentiality to induce oestrus was assessed. It was noticed that the bedding of all the males proved to be a stimulus inducing oestrus in the majority of the females during the 7 day exposure. There was no significant difference in the number of females returning to oestrus following exposure to soiled bedding of different males. These results elucidate that environmental factors, especially light and temperature do not influence the production/release of the oestrus-inducing pheromone in wild mice.

Animals↗
PubMed1989

Study of maternal behaviour in wild mice: avoidance to retrieve young and increase in cannibalic activity.

Pregnant females trapped from the wild were watched daily for parturition. Postpartum-retrieving reaction tests were carried out with all mothers using their own, alien or mixed pups. All the females when release in the cage for testing roamed around the cage but did not tend to retrieve any of the pups. Females frequently sniffed their own pups as well as alien ones without displaying any discrimination. However, when these females were left with their pups for rearing after the tests, they tended to cannibalize the latter. These findings indicate the absence of maternal retrieving in wild species of Mus, at least, under laboratory conditions.

Animals↗
PubMed1988

Male-induced puberty acceleration in young female wild mice: hormonal regulation and source of pheromonal cue.

Experiments were designed to examine the influence of adult males on the rate of sexual maturation in young female wild mice. In one experiment, young females were raised in presence of adult males, adult females and in absence of any individual, while in another, they were exposed to urines of: (1) castrated males, (2) spayed females, (3) castrated and TP-treated males, (4) castrated and placebo-injected males. Female maturation as measured by age at vaginal opening and first vaginal oestrus was accelerated by presence of adult males, whereas presence of adult females considerably delayed the vaginal opening and the appearance of first oestrus in young females. In the other set of the experiments, urine from castrated or castrated and placebo-injected males was ineffective in inducing early puberty while urine from spayed females highly delayed the sexual maturation. By contrast, urine from castrated and TP-treated males accelerated the puberty more or less like normal males. The results indicate that male's chemosignal accelerating puberty in young females is present in urine and its production is under the control of androgens. However, the female-originating urinary pheromone which delays the puberty in young females is not regulated by ovarian hormones.

Animals↗
PubMed1986

Oestrus suppression in wild mice: source of pheromonal cue.

Regularly cycling female mice attained anoestrus when they were exposed to voided urine or to urine directly collected from the bladder of intact females. In contrast, the urine of spayed females or the clitoral gland homogenate from intact females was found ineffective in suppressing oestrus. The findings thus clearly elucidate the presence of an oestrous-suppressing pheromone in the urine of intact females whether voided or collected directly from the bladder and confirm the oestrogen dependence of the pheromone. Clitoral glands do not seem to have a role in production of this pheromone.

Animals↗
PubMed1975

Increased disaccharidase activity in human diabetics.

Disaccharidase activity has been shown to be increased in human diabetics. Diabetics controlled on diet therapy showed no change in disaccharidase activity while two diabetics controlled on insulin or insulin-producing drug, glibenclamide, showed a fall in disaccharidase values toward normal. Possible causes for the increased disaccharidase activity in diabetes are discussed.

Adult↗