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S Bhadra

Publications and source records attributed to S Bhadra.

80 records · Page 5Linked to original sources
PubMed1989

The pentylenetetrazol-like interoceptive stimulus produced by ethanol withdrawal is potentiated by bicuculline and picrotoxinin.

We investigated whether the interoceptive discriminative stimulus (IDS) arising from ethanol withdrawal was related to decreased activity of the gamma-aminobutyric acid (GABA) system by determining whether the sensitivity of rats to the GABA antagonists was altered by chronic treatment with ethanol. Rats were trained to obtain food reward by responding on one lever following pentylenetetrazol (PTZ) and the other lever following saline. Whereas all of the trained rats selected the PTZ-appropriate lever after PTZ, no more than 50% of them selected this lever following an optimum dose of bicuculline or picrotoxinin. After either saline or diazepam (5 mg/kg), all of the rats selected the saline-appropriate lever. Ethanol (0.24 mol/kg/day) was then administered to the rats for 4 days via a nutritionally balanced liquid diet. Between 48 and 96 hours postethanol, 30% of the rats selected the PTZ-appropriate lever following saline, whereas selection of this lever was increased to 80% following either bicuculline or picrotoxinin. Thus, further antagonism of GABAergic activity increased the subjective effect of ethanol withdrawal. These data support the hypothesis that the PTZ-like IDS produced during withdrawal from ethanol is related to an ethanol-induced deficit in the activity of the GABA-benzodiazepine receptor-coupled chloride channel.

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PubMed1988

Characterization of a pentylenetetrazol-like interoceptive stimulus produced by ethanol withdrawal.

Rats were trained with food reinforcement to discriminate the anxiogenic drug pentylenetetrazol (PTZ, 20 mg/kg) from saline in a two-lever-choice task. In Experiment 1, ethanol, 8.25% w/v was given by gavage (7/day) for 4 days, with doses titrated to maintain moderate intoxication. After termination of ethanol, the rats exhibited mild overt signs of withdrawal and, in discrimination tests with saline as the test substance, they selected the PTZ lever, an effect reversed by ethanol, 2 g/kg, and by diazepam, 5 mg/kg. In Experiment 2, rats drank a nutritionally complete liquid diet containing ethanol, 4.5% w/v, for 1 week. They became tolerant to the intoxicating effect of ethanol, and blood ethanol concentration mounted with continued dosing. On termination of chronic ethanol, rats selected the PTZ lever before the onset of overt physical signs of withdrawal, and both measures returned to base line within 3 days. In Experiment 3 the percentage of rats selecting the PTZ lever after termination of ethanol depended upon the dose (up to 12.5 g/kg) and duration (up to a ceiling effect by 3 days) of ethanol administered chronically. These results indicate that a PTZ-like stimulus produced interoceptively can be demonstrated in the rat as an objective measure of ethanol withdrawal. This paradigm may provide insight into the symptom of anxiety associated with ethanol withdrawal.

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PubMedDate not supplied

Effect of enteral feeding on hepatic steatosis induced by total parenteral nutrition.

This study was designed to test the hypothesis that deprivation of enteral feeding contributes to the development of total parenteral nutrition (TPN)-induced hepatic dysfunction and that alterations of gut hormones are involved in its pathogenesis. Twenty-one adult Sprague-Dawley rats were randomized into three groups: group 1 received chow feeding ad libitum (288 kcal/kg per day); group 2 received dextrose-based TPN (320 +/- 5 kcal/kg per day); and group 3 received TPN (315 +/- 15 kcal/kg per day) plus chow feeding ad libitum (74 +/- 1 kcal/kg per day). After 7 days, portal blood was assayed for insulin, glucagon, gastrin, peptide YY, secretin, and vasoactive intestinal polypeptide; systemic blood for determination of liver function tests and serum lipid analysis. Liver biopsies were taken for histology and staining for fat, and the remainder of the livers were removed for tissue lipid analysis. TPN induced striking hepatic steatosis with prominent histologic changes and accumulation of lipids, mainly triglycerides and cholesterol ester, in the liver. Addition of enteral feeding to TPN-treated animals significantly reduced the histologic changes as well as lipid accumulation in the liver. Portal plasma levels of gastrin and peptide YY were reduced in animals maintained on TPN alone, with no change in secretin or vasoactive intestinal polypeptide levels. Enteral supplementation increased peptide YY levels in group 3, but not to normal, while gastrin secretion remained decreased. The serum triglyceride levels were decreased in both TPN groups; no differences were detected in the serum cholesterol levels or liver function tests.(ABSTRACT TRUNCATED AT 250 WORDS)

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