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Biomedical subjects

R F Mucha

Publications and source records attributed to R F Mucha.

10 recordsLinked to original sources

Increased weight gain as a morphine withdrawal response in rats.

Adult male Wistar rats injected daily with 20 or 200 mg/kg morphine-SO4 for 35 days suffered a dose-dependent weight loss over the first 3 days of morphine withdrawal. However, during the next 28 days they gained weight more rapidly than controls, the rates being related to the previous morphine dosage. These findings were replicated in Sprague-Dawley rats treated for 26 days with 60 mg/kg morphine. Food-restricted controls suffering weight losses equal to those of the morphine-treated or morphine-withdrawn groups did not subsequently gain weight as rapidly as the latter groups. Therefore the rapid post-withdrawal weight gain may be a true adaptive response to the weight suppressing effects of morphine. Also, comparisons of weight changes during treatment in the two experiments indicated possible strain differences for tolerance to morphine's direct weight-reducing effect.

Animals

Effect of desglycinamide(9)-lysine(8)-vasopressin and prolyl-leucyl-glycinamide on oral ethanol intake in the rat.

Rats given ethanol in their drinking water at a concentration that permitted adequate fluid intake gradually accepted higher concentrations and consumed larger amounts of ethanol. These increases were augmented when daily subcutaneous injections of 1 microgram of desglycinamide9-lysine8-vasopressin (DGLVP) or 10 microgram of prolyl-leucyl-glycinamide (PLG) were given concomitantly. Nonsignificant changes in ethanol consumption were seen with injections of 1 microgram PLG, or 0.42 or 42 microgram of lysine8-vasopressin (LVP). In a second experiment 4 microgram DGLVP given every second day as a long-acting zinc phosphate complex, commencing after the increases in ethanol intake had taken place, failed to produce any change in ethanol consumption subsequently. In both Experiments 1 and 2, the rats were switched from forced ethanol intake to a choice between ethanol and tap water. On these tests there was only marginal evidence of peptide-produced changes in ethanol intake.

Alcohol Drinking

Kindling-related changes in afterdischarge "thresholds".

Amygdaloid stimulations were applied to rats at gradually increasing current intensities once every 60 sec until and afterdischarge (AD) was recorded through the stimulation electrode. These initial AD "thresholds" (x = 75 muA) were reduced over a 4-day period by a series of 12 subthreshold stimulations. In contrast, stimulations administered on the same regimen but at a higher intensity (400 muA) had raised the AD threshold. The decreases in the AD threshold were relatively permanent, whereas the elevated thresholds were subsequently reduced to control levels by a series of subthreshold stimulations or by a 7-day stimulation-free period. Two days following the completion of Experiment 1, all of the rats were injected with a low dose of pentylenetetrazol. The incidence of pentylenetetrazol-induced epileptic symptoms was much higher in the experimental animals than in the control subjects previously subjected only to the threshold estimation procedure.

Amygdala