Effect of compound 48/80 on the thalamic mast cells, serotonin level and corticosterone secretion in rats.
The effect of thalamic mast cells (MCs) degranulation and serotonin liberation by compound 48/80 on the hypothalamic-pituitary-adrenocortical (HPA) activity, measured indirectly through corticosterone secretion, was investigated in conscious rats. All drugs were given intracerebroventricularly (icv), the serotonin antagonists 15 min prior to compound 48/80. One hour after administration, compound 48/80 (1 and 5 micrograms) caused a significant increase in degranulated MC number in the thalamus, from control value of 20% up to 58%, and a considerable rise in the serum corticosterone level, but only minor diminution of the thalamic serotonin content. Pretreatment with methysergide, a serotonin receptor antagonist, only slightly dimished the compound 48/80-induced corticosterone response, while pretreatment with cyproheptadine, an antagonist of serotonin-histamine and cholinergic-receptors, significantly decreased the compound 48/80-elicited corticosterone response. These results show for the first time that thalamic mast cells contain a very small amount of serotonin, which may play only a minor role in increasing the HPA activity by compound 48/80. These findings also suggest that other mediators liberated from mast cells by compound 48/80 are responsible for the considerable increase in the HPA activity.
Bugajski
J
J
Department of Pathophysiology, Jagiellonian University School of Medicine, Kraków, Poland.
Bugajski
A J
AJ
Chłap
Z
Z
Borycz
J
J
D000818:Animals; D003345:Corticosterone / Q000097:blood*; D003533:Cyproheptadine / Q000008:administration & dosage / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D008784:Methysergide / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism*; D013788:Thalamus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D003189:p-Methoxy-N-methylphenethylamine / Q000008:administration & dosage / Q000494:pharmacology*
D003533:Cyproheptadine; D012701:Serotonin; D003189:p-Methoxy-N-methylphenethylamine; D003345:Corticosterone; D008784:Methysergide