Histaminergic neurons mediate restraint stress-induced activation of central 5-hydroxytryptaminergic neurons in the rat.
The role of histamine in mediating restraint stress-induced increases in the activity of central 5-hydroxytryptaminergic neurons was evaluated in male rats. 5-Hydroxytryptaminergic neuronal activity was estimated by measuring concentrations of the 5-hydroxytryptamine (5-HT) metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the nucleus accumbens and suprachiasmatic nucleus which contain terminals of these neurons. Placement of rats within restraining tubes rapidly increased (within 10 min) 5-HIAA concentrations in the nucleus accumbens and suprachiasmatic nucleus. Depletion of neuronal histamine by alpha-fluoromethylhistidine or antagonism of histamine H1 receptors by mepyramine prevented stress-induced increases in 5-HIAA concentrations, whereas blockade of histamine H2 receptors by zolantidine was without effect. Neither alpha-fluoromethylhistidine, mepyramine nor zolantidine affected basal 5-HIAA concentrations in either brain region. These results indicate that histaminergic neurons mediate stress-induced increases in the activity of central 5-hydroxytryptaminergic neurons via an action at histamine H1 receptors.
Fleckenstein
A E
AE
Department of Pharmacology and Toxicology, Michigan State University, East Lansing 48824.
Lookingland
K J
KJ
Moore
K E
KE
D000818:Animals; D052160:Benzothiazoles; D006632:Histamine / Q000378:metabolism*; D006635:Histamine H2 Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D006640:Histidine Decarboxylase / Q000037:antagonists & inhibitors; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism*; D008297:Male; D008762:Methylhistidines / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009714:Nucleus Accumbens / Q000378:metabolism*; D050198:Phenoxypropanolamines; D010880:Piperidines / Q000008:administration & dosage / Q000494:pharmacology; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D011969:Receptors, Histamine H1 / Q000187:drug effects; D012149:Restraint, Physical; D012701:Serotonin / Q000378:metabolism*; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D013844:Thiazoles / Q000008:administration & dosage / Q000494:pharmacology
D052160:Benzothiazoles; D006635:Histamine H2 Antagonists; D008762:Methylhistidines; D050198:Phenoxypropanolamines; D010880:Piperidines; D011969:Receptors, Histamine H1; D013844:Thiazoles; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; C028309:alpha-fluoromethylhistidine; D006632:Histamine; D006640:Histidine Decarboxylase; D011738:Pyrilamine; C055302:zolantidine