Participation of sympathetic and vagal tones in the hypotensive and bradycardic effects of some 5-HT1-like receptor agonists in the rat.
In normotensive anaesthetized rats, 8-OH-DPAT, RU 24969 and 5-MeODMT, three 5-HT1-like receptor agonists, decreased blood pressure and heart rate. The decrease in blood pressure was suppressed by pithing or pretreatment with hexamethonium. Bilateral section of the vagus nerves, pretreatment with a beta-adrenoceptor blocking agent or with atropine, combination of bivagotomy plus beta-adrenoceptor blockade strongly reduced the bradycardia. These results are compatible with a centrally-mediated decrease in sympathetic tone and increase in vagal tone, as the cause of the hypotension and bradycardia induced by these 5-HT1-like receptor agonists in normotensive anaesthetized rats.
Cherqui
C
C
INSERM-U 228, Faculté de Médecine Broussais Hôtel-Dieu, Paris, France.
Dabiré
H
H
Fournier
B
B
Schmitt
H
H
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D011969:Receptors, Histamine H1 / Q000187:drug effects*; D011978:Receptors, Nicotinic / Q000187:drug effects; D013564:Sympathetic Nervous System / Q000187:drug effects*; D013764:Tetrahydronaphthalenes / Q000494:pharmacology; D014630:Vagus Nerve / Q000187:drug effects*
D008732:Methoxydimethyltryptamines; D011942:Receptors, Adrenergic, alpha; D011969:Receptors, Histamine H1; D011978:Receptors, Nicotinic; D013764:Tetrahydronaphthalenes; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D009638:Norepinephrine