A 5-hydroxytryptamine lesion markedly reduces the incidence of burst-firing dorsal raphe neurones in the rat.
Recently, we described neurones in the rat dorsal raphe nucleus (DRN) with electrophysiological characteristics typical of 5-hydroxytryptamine (5-HT) neurones except that the neurones fired brief bursts. Here we report the effect of 5-HT lesions on the incidence of these burst-firing neurones. In vivo extracellular recordings revealed that in rats pretreated with the selective 5-HT neurotoxin, 5,7-dihydroxytryptamine, the occurrence of typical 5-HT neurones was significantly decreased (80%) compared to controls. In these 5-HT lesioned animals, the number of the burst-firing DRN neurones was also significantly reduced (91%). Neurones previously characterised as not containing 5-HT, were not altered by the lesion. These data are further evidence to support our hypothesis that burst-firing neurones in the DRN contain 5-HT.
Hajos
M
M
Department of Clinical Pharmacology, Oxford University, Radcliffe Infirmary, UK. mihaly.hajos@clinical-pharmacology.oxford.ac.uk
Sharp
T
T
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D004396:Coloring Agents; D004594:Electrophysiology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D010507:Periodicity; D011903:Raphe Nuclei / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000494:pharmacology*; D018490:Serotonin Agents / Q000494:pharmacology
D004396:Coloring Agents; D018490:Serotonin Agents; D015116:5,7-Dihydroxytryptamine; D012701:Serotonin