title: The effects of beta-carbolines on responses to acetylcholine, noradrenaline, 5-hydroxytryptamine and amino acids in the rat spinal cord.
abstract: Various drugs have been applied electrophoretically to Renshaw cells and to unidentified spinal neurones in pentabarbitone anaesthetized or decerebrated rats. Responses to noradrenaline (NA) and 5-hydroxytryptamine (5-HT) have not previously been described at this site and were of two types; either monophasic depression or biphasic depression-excitation. The effect of harmine on these responses was examined. Harmine and harmaline were also tested on the excitant responses to acetylcholine (ACh) and DL-homocysteate (DLH), and on the depressant responses to glycine and gamma-aminobutyric acid (GABA). On some cells harmaline antagonized ACh, but not DLH, and glycine, but not GABA, responses. Harmine caused only non-specific depression and spike configuration changes. The effects of harmine on NA and 5-HT responses were usually non-specific, and any anatagonism was usually accompanied by, or soon followed by spike changes. LSD was also tested on the amine responses. LSD itself had a clear depressant effect on neuronal firing rates. It could either antagonize or potentiate NA and 5-HT depressant responses, but the antagonism in particular was closely followed by spike changes. Somewhat more specific antagonism of the late excitation was seen.
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects*; D000818:Animals; D002243:Carbolines / Q000494:pharmacology*; D004347:Drug Interactions; D005998:Glycine / Q000494:pharmacology; D006246:Harmaline / Q000494:pharmacology; D006247:Harmine / Q000494:pharmacology; D006710:Homocysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology*; D008238:Lysergic Acid Diethylamide / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology*; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*; D013116:Spinal Cord / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D002243:Carbolines; D007211:Indoles; D006710:Homocysteine; D012701:Serotonin; D006247:Harmine; D005680:gamma-Aminobutyric Acid; D008238:Lysergic Acid Diethylamide; D006246:Harmaline; D000109:Acetylcholine; D005998:Glycine; D009638:Norepinephrine