Muscarinic M2 receptors inhibit heat-induced CGRP release from isolated rat skin.
The action of cholinergic agonists on modulating basal and heat-induced CGRP release was investigated in isolated rat skin. Nicotine (10(-6), 10(-5) and 10(-4) M) induced a bimodal increase of CGRP release, that was significant for the two larger concentrations (by 113 and 36%, respectively). On the contrary, muscarine (10(-4) M) and arecaidine (10(-5) M) significantly decreased the basal CGRP release (by 16 and 23%, respectively). The substantial increase of CGRP release evoked by noxious heat (47 degrees C) remained unaltered upon co-application of nicotine, but was diminished by 35% upon muscarine. Arecaidine was more effective in this respect causing significant dose-dependent depressions by 30% (at 10(-6) M) and by 60% (at 10(-5) M). These data support a role of muscarinic M2 receptors in nociceptor desensitization.
Bernardini
N
N
Department of Physiology and Experimental Pathophysiology, University of Erlangen, Universitätsstr. 17, D-91054 Erlangen, Germany.
Reeh
P W
PW
Sauer
S K
SK
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001115:Arecoline / Q000031:analogs & derivatives* / Q000494:pharmacology; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006358:Hot Temperature; D066298:In Vitro Techniques; D008297:Male; D009116:Muscarine / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology; D051381:Rats; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic / Q000378:metabolism*; D012867:Skin / Q000378:metabolism*
D018721:Muscarinic Agonists; D018722:Nicotinic Agonists; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic; C015688:arecaidine; D001115:Arecoline; D009538:Nicotine; D009116:Muscarine; D015740:Calcitonin Gene-Related Peptide; D000109:Acetylcholine