Effects of cyclic AMP-affecting agents on contractile reactivity of isolated mesenteric and renal resistance arteries of the rat.
1. Effects of adenosine 3':5'-cyclic monophosphate (cyclic AMP)-affecting agents were compared in mesenteric and renal resistance arteries that had been isolated from 20 week old Wistar-Kyoto rats, chemically sympathectomized, stretched to their optimal diameter for mechanical performance and made to contract in response to 30 mM potassium. 2. In mesenteric resistance arteries, isoprenaline, dopamine, NaF, forskolin, isobutyl-methylxanthine, milrinone and dibutyryl-cyclic AMP induced relaxation. Clonidine induced further increases in tension that could be reduced by pertussis toxin and prazosin but not by yohimbine. Clonidine also reduced relaxant responses to isoprenaline. 3. In renal resistance arteries, isoprenaline and dopamine failed to induce relaxation. Compared to mesenteric resistance arteries, renal vessels were less sensitive to the relaxant effect of NaF, forskolin and isobutyl-methylxanthine. Relaxant responses to dibutyryl-cyclic AMP did not differ between the two resistance arteries. 4. Indirect evidence thus suggests that in mesenteric resistance arteries, adenylate cyclase is susceptible to pharmacological activation and inhibition and is functionally coupled to relaxation. The refractory nature of renal resistance arteries to the relaxant effects of isoprenaline and dopamine could be due primarily to absence of appropriate receptors and to a relatively low activity of adenylate cyclase.
Heesen
B J
BJ
Department of Pharmacology, University of Limburg, Maastricht, The Netherlands.
De Mey
J G
JG
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D001158:Arteries / Q000187:drug effects; D003994:Bucladesine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology*; D015232:Dinoprostone / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D066298:In Vitro Techniques; D007537:Isometric Contraction; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D020105:Milrinone; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D037342:Pertussis Toxin; D011728:Pyridones / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D011943:Receptors, Adrenergic, beta / Q000187:drug effects; D012079:Renal Circulation / Q000187:drug effects*; D012969:Sodium Fluoride / Q000494:pharmacology; D013562:Sympathectomy; D014655:Vascular Resistance / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D037361:Adenylate Cyclase Toxin; D011728:Pyridones; D011943:Receptors, Adrenergic, beta; D014665:Vasodilator Agents; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D003994:Bucladesine; D012969:Sodium Fluoride; D000242:Cyclic AMP; D037342:Pertussis Toxin; D000262:Adenylyl Cyclases; D020105:Milrinone; D015232:Dinoprostone; D007545:Isoproterenol; D015056:1-Methyl-3-isobutylxanthine