Relaxation of rat arteries by urocortin: effects of gender and diabetes.
Urocortin is a peptide recently identified, structurally related to corticotropin releasing factor (CRF). We have compared the effects of urocortin in different vascular beds, and have investigated whether there are gender differences in these effects or whether they are altered by diabetes. We have studied the response of isolated segments (2-mm long) from basilar, coronary and tail arteries to urocortin. The segments were obtained from male and female, normoglycaemic and streptozotocin-induced diabetic rats. In the arterial segments precontracted with endothelin-1, urocortin produced concentration-dependent relaxation, and the order of sensitivity was: tail > basilar > coronary. This relaxation was similar in arteries from male and female, diabetic and normoglycaemic rats. In tail arteries from normoglycaemic male rats, the cyclooxygenase inhibitor meclofenamate (10(-5) M) increased the relaxation to urocortin, and the inhibitor of nitric oxide synthesis N(omega)-nitro-L-arginine methyl ester (L-NAME, 10(-4) M) or the potassium-channel-blocker charybdotoxin (10(-7) M) did not modify it. In tail arteries from normoglycaemic female rats meclofenamate, charybdotoxin or L-NAME did not modify the relaxation to urocortin. These results suggested that urocortin produced vasodilation which showed regional differences between basilar, coronary and tail arteries, but was not affected by diabetes. The mechanisms underlying this relaxation in tail arteries might differ between males and females.
Sanz
Elena
E
Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma, Arzobispo Morcillo 2, 28029 Madrid, Spain.
Fernández
Nuria
N
Monge
Luis
L
Climent
Belén
B
Diéguez
Godofredo
G
Garcia-Villalón
Angel Luis
AL
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D003921:Diabetes Mellitus, Experimental; D005260:Female; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D019331:NG-Nitroarginine Methyl Ester / Q000037:antagonists & inhibitors; D018696:Neuroprotective Agents / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects; D051381:Rats; D012737:Sex Factors; D054832:Urocortins; D014664:Vasodilation / Q000187:drug effects*
D018696:Neuroprotective Agents; D015221:Potassium Channels; D054832:Urocortins; D003346:Corticotropin-Releasing Hormone; D019331:NG-Nitroarginine Methyl Ester