Effects of methoxamine on spontaneous uterine activity and blood flow of the rat uterus 'in vivo'.
The vascular (blood pressure, heart rate and peripheral blood flow) and uterine (spontaneous motility) responses to intravenous methoxamine were studied in anaesthetized rats pre-treated with diethylstilboestrol. Methoxamine produced an increase (0.5-2 mg/kg) or did not modify (0.01 and 3 mg/kg) spontaneous uterine motility. The alpha 1-agonist also induced a hypertensive effect (0.1-3 mg/kg) accompanied by bradycardia at the highest doses, and a decrease in blood flow significantly greater in intestinal than uterine tissues. These effects were abolished by prazosin. The uterine action of methoxamine in vivo appears to result from the balance between myometrial alpha 1-excitatory effect and vascular alpha 1-vasoconstriction which induced uterine inhibition. The oestrogens appear to protect the alpha 1-mediated vasoconstriction.
Palop
V
V
Departament de Farmacologia, Facultat de Medicina i Odontologia, Universitat de València, España.
Tarazona
E
E
Martinez-Mir
I
I
Estañ
L
L
Morales-Olivas
F J
FJ
Rubio
E
E
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004054:Diethylstilbestrol / Q000008:administration & dosage; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D008729:Methoxamine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow / Q000187:drug effects; D014590:Uterine Contraction / Q000187:drug effects*; D014599:Uterus / Q000098:blood supply*
D004054:Diethylstilbestrol; D008729:Methoxamine