Effects of serotonin and the 5-HT2/1C receptor agonist DOI on neurons of the cerebellar dentate/interpositus nuclei: possible involvement of a GABAergic interneuron.
The present study was designed to examine the effects of iontophoretically applied serotonin (5-HT) on neurons of the cerebellar dentate/interpositus nuclei in an in vitro slice preparation and to determine if the 5-HT2/1C receptor subtype could be responsible for mediating any effects noted with 5-HT. 5-HT and the 5-HT2/1C-selective agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI) were iontophoretically applied alone and during superfusion of the 5-HT2/1C-selective antagonist, ritanserin. 5-HT and DOI elicited either inhibition or excitation of the spontaneous activity of dentate/interpositus neurons. An inhibitory response was induced by both compounds in the majority of cells responding. Ritanserin significantly attenuated the inhibitory response elicited by both 5-HT and DOI. In addition, the inhibitory response to DOI was significantly attenuated by the gamma-aminobutyric acid (GABA) antagonists, bicuculline and picrotoxin. Our results suggest that the 5-HT2/1C receptor subtype may be partially responsible for mediating 5-HT-induced inhibition of dentate/interpositus neurons, possibly via activation of GABAergic interneurons.
Cumming-Hood
P A
PA
Texas Tech University Health Sciences Center, Department of Physiology, Lubbock 79430.
Strahlendorf
H K
HK
Strahlendorf
J C
JC
D000200:Action Potentials / Q000187:drug effects*; D000662:Amphetamines / Q000494:pharmacology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002529:Cerebellar Nuclei / Q000187:drug effects*; D007395:Interneurons / Q000187:drug effects* / Q000502:physiology; D007478:Iontophoresis; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects*; D010852:Picrotoxin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016713:Ritanserin / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D000662:Amphetamines; D001640:Bicuculline; D010852:Picrotoxin; D016713:Ritanserin; D012701:Serotonin; D017366:Serotonin Receptor Agonists; D005680:gamma-Aminobutyric Acid; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine