Calcium Signaling/drug effects; Mesenteric Arteries/drug effects; Nitric Oxide Synthase Type III/metabolism; Raloxifene Hydrochloride/pharmacology; Selective Estrogen Receptor Modulators/pharmacology; Vasodilation/drug effects; Vasodilator Agents/pharmacology; Androstadienes/pharmacology; Animals; Apamin/pharmacology; Blood Pressure/drug effects; Charybdotoxin/pharmacology; Chromones/pharmacology; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors/pharmacology; Estradiol/analogs & derivatives; Estradiol/pharmacology; Estrogen Antagonists/pharmacology; Female; Fulvestrant; In Vitro Techniques; Male; Mesenteric Arteries/enzymology; Morpholines/pharmacology; NG-Nitroarginine Methyl Ester/pharmacology; Nitric Oxide/metabolism; Nitric Oxide Synthase Type III/antagonists & inhibitors; Ovariectomy; Phosphorylation; Potassium Channel Blockers/pharmacology; Protein Kinase Inhibitors/pharmacology; Rats; Rats, Sprague-Dawley; Sex Factors; Time Factors; Vascular Resistance/drug effects; Wortmannin