Sex differences in extracellular and intracellular calcium-mediated vascular reactivity to vasopressin in rat aorta.

Sex differences in extracellular and intracellular calcium-mediated vascular reactivity to vasopressin in rat aorta.

Eatman D; Stallone J N; Rutecki G W; Whittier F C

European journal of pharmacology

1998

1998-11

In rat thoracic aorta, contractile responses to arginine vasopressin are two-fold higher in females than in males. To determine the roles of extracellular and intracellular Ca2+ in this sexual dimorphism in vascular function, vascular reactivity and Ca2+ channel function were examined in thoracic aortae of male and female rats. In the presence of diltiazem (10 microM), maximal contraction to vasopressin was reduced to a greater extent in male (65+/-2%) than in female aortae (38+/-1%). Maximal contractile responses to KCl and Bay K 8644 were similar in male and female aortae. Sensitivity to KCI was slightly but significantly higher in male than in female aorta; in contrast, sensitivity to Bay K 8644 was nearly three-fold higher in males than in females. Removal of the endothelium enhanced sensitivity to KCl similarly in male and female aortae. In the presence of simvastatin (60 microM; an inhibitor of intracellular Ca2+ release), reactivity to vasopressin was reduced substantially in female (42+/-1%) but unaltered in male aortae. Removal of the endothelium enhanced the inhibitory effect of simvastatin in both female (73+/-2%) and male aortae (41+/-2%). These findings demonstrate that male aortae depend more upon extracellular Ca2+ influx, whereas female aortae depend more upon intracellular Ca2+ release for vasopressin-induced contraction.

*Sex Characteristics; 1; 3-Pyridinecarboxylic acid; 4-dihydro-2; 6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-; Animals; Aorta/drug effects/*metabolism; Calcium Channel Agonists/*pharmacology; Calcium Channel Blockers/*pharmacology; Calcium/*metabolism; Diltiazem/pharmacology; Dose-Response Relationship; Drug; Female; In Vitro Techniques; Male; Methyl ester/pharmacology; Potassium Chloride/pharmacology; Rats; Simvastatin/pharmacology; Sprague-Dawley; Vasoconstriction/*drug effects; Vasopressins/*metabolism

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

207–216

2

361