Hyposensitivity to serotonergic stimulation in protein malnourished rats.
Rats subjected to early protein malnutrition have higher levels of brain serotonin (5-HT) than well-nourished rats. In the present study we asked whether the elevated 5-HT levels of associated with any changes in sensitivity to serotonergic stimulation. In four different behavioral tets the effects of the 5-HT agonist N,N-dimethyltryptamine (DMT) were, with only a few exceptions, smaller in rats malnourished during both pre- and postweaning stages of development or during just one period or the other. In Experiment 1 the 5-HT syndrome induced by DMT was weaker in malnourished rats than in well-nourished ones. In Experiments 2 and 3, DMT was not a disruptive to malnourished rats in two motor tasks, rotating rod and treadmill, as it was to rats reared under high protein conditions. In Experiment 4 reductions in acoustic startle amplitudes induced by DMT were not as large in malnourished as in well-nourished rats. The hyposensitivity to DMt in protein malnourished rats may reflect a diminished sensitivity of 5-HT receptors resulting from the abnormally high levels of the neurotransmitter.
D000818:Animals; D001835:Body Weight; D004044:Dietary Proteins / Q000008:administration & dosage; D005260:Female; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects*; D004130:N,N-Dimethyltryptamine / Q000494:pharmacology*; D011488:Protein Deficiency / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013216:Reflex, Startle / Q000187:drug effects*; D012701:Serotonin / Q000378:metabolism*; D014363:Tryptamines / Q000494:pharmacology*
D004044:Dietary Proteins; D014363:Tryptamines; D012701:Serotonin; D004130:N,N-Dimethyltryptamine; D008784:Methysergide