Anaphylatoxin C5a modulation of an alpha-adrenergic receptor system in the rat hypothalamus.
C5a anaphylatoxin injected via implanted cannulae into the perifornical region of the hypothalamus stimulated eating in sated rats. C5a also attenuated carbamyl choline-induced drinking, and carbamyl choline inhibited C5a-induced eating, a mutual inhibition characteristic of the adrenergic-cholinergic interactions at this site. The increased food intake induced by C5a was also reversed by phentolamine, an alpha-adrenergic antagonist. Granulocytes infiltrating as a result of C5a-mediated leukotaxis did not arrive at the site in time to influence C5a activity. We propose that C5a in some way activates an alpha-adrenergic receptor system in the hypothalamus, and that anaphylatoxins could mediate neuropsychiatric symptoms sometimes associated with immune complex diseases affecting the central nervous system.
Williams
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CA
Schupf
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N
Hugli
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TE
D000818:Animals; D001522:Behavior, Animal; D002634:Chemotaxis, Leukocyte; D003182:Complement C5 / Q000494:pharmacology / Q000502:physiology*; D015936:Complement C5a; D004306:Dose-Response Relationship, Immunologic; D004435:Eating / Q000187:drug effects; D007031:Hypothalamus / Q000648:ultrastructure*; D008297:Male; D009504:Neutrophils / Q000276:immunology; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects* / Q000276:immunology
D003182:Complement C5; D011942:Receptors, Adrenergic, alpha; D015936:Complement C5a