The effect of tryptamine on serotonin release from hypothalamic slices is mediated by a cholinergic interneurone.
Tryptamine produced a concentration-related inhibition of potassium-evoked release of tritium from slices of rat hypothalamus preloaded with 3H-serotonin. This effect of tryptamine was blocked by a series of serotonin antagonists with a relative order of potency which suggested that tryptamine was acting on a post-junctional serotonin receptor. However, the response to tryptamine was also blocked by tetrodotoxin, indicating that tryptamine may be acting indirectly via the release of a second neurotransmitter. The finding that physostigmine enhanced, whilst atropine antagonised the effect of tryptamine suggests that the second neurotransmitter may be acetylcholine. This possibility is discussed.
D000818:Animals; D002799:Cholinergic Fibers / Q000187:drug effects* / Q000378:metabolism; D002997:Clomipramine / Q000494:pharmacology; D046508:Culture Techniques; D007031:Hypothalamus / Q000187:drug effects* / Q000378:metabolism; D007395:Interneurons / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D009115:Muridae; D010830:Physostigmine / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000378:metabolism*; D014363:Tryptamines / Q000494:pharmacology*
D011985:Receptors, Serotonin; D014363:Tryptamines; D012701:Serotonin; C030820:tryptamine; D010830:Physostigmine; D002997:Clomipramine; D011188:Potassium; D008784:Methysergide