Neuronal responses to delta 9-tetrahydrocannabinol in the solitary tract nucleus.
The effects of delta 9-tetrahydrocannabinol on single-unit activity in the subpostremal division of the nucleus tractus solitarii were investigated by extracellular recording in rat brain slices. The spontaneous firing rate of 54.8% of the recorded neurons was significantly changed after bath applications of delta 9-tetrahydrocannabinol. Putative nutrition-related neurons responding to a moderate increase in glucose concentration were selectively sensitive to delta 9-tetrahydrocannabinol. The delta 9-tetrahydrocannabinol-sensitive neurons were depressed by clonidine and are therefore likely to be adrenergic or noradrenergic. These observations suggest that some catecholaminergic, glucose-responsive neurons in the subpostremal nucleus tractus solitarii might mediate the influence of cannabinoids on feeding behaviour. Furthermore, most delta 9-tetrahydrocannabinol-sensitive neurons in the nucleus tractus solitarii showed opposite responses to delta 9-tetrahydrocannabinol and the 5-HT3 receptor agonist 1-phenylbiguanide, and might therefore be involved in the nausea-reducing effects of cannabinoids.
Himmi
T
T
Laboratoire de Neurobiologie, UPR 9024-CNRS, Université de Provence, Marseille, France.
Dallaporta
M
M
Perrin
J
J
Orsini
J C
JC
D000818:Animals; D001645:Biguanides / Q000494:pharmacology; D003000:Clonidine / Q000494:pharmacology; D013759:Dronabinol / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017552:Solitary Nucleus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism
D001645:Biguanides; D013759:Dronabinol; D005947:Glucose; D003000:Clonidine; C008846:phenyl biguanide