Independent effects of cholinergic and serotonergic lesions on acetylcholine and serotonin release in the neocortex of the rat.
Rats received a unilateral lesion of the nucleus basalis magnocellularis (NBM) by infusion of ibotenic acid. In addition, the dorsal raphe nucleus was lesioned by infusion of 5,7-dihydroxytryptamine (5,7-DHT). The release of acetylcholine (ACh), choline, serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) was measured in the frontal neocortex by means of microdialysis. Lesions of the NBM, but not the raphe nucleus, reduced the release of ACh significantly (-47%). The release of 5-HT and 5-HIAA was reduced by raphe lesions (-44% and -79%+), but not by NBM lesions. In no case did the combined lesion affect neurotransmitter release more than a single lesion. These results suggest that serotonergic projections from the dorsal raphe nucleus are not involved in tonic inhibition of ACh release in the neocortex.
Dekker
A J
AJ
Department of Neurosciences, University of California and Neurology Service, VA Medical Center, San Diego 92161.
Thal
L J
LJ
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D003956:Dialysis; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007051:Ibotenic Acid / Q000494:pharmacology; D008297:Male; D011903:Raphe Nuclei / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D012701:Serotonin / Q000378:metabolism*; D014726:Vestibular Nuclei / Q000187:drug effects / Q000502:physiology*
D007051:Ibotenic Acid; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D002795:Choline O-Acetyltransferase; D000109:Acetylcholine