M3 cholinoceptors and P2y purinoceptors mediating relaxation of arteries in spontaneously hypertensive rats at prehypertensive stages.
Muscarinic cholinoceptor and purinoceptor subtypes were determined in femoral and mesenteric artery strips from spontaneously hypertensive rats (SHR) at prehypertensive stages. Acetylcholine (ACh), carbachol and oxotremorine induced endothelium-dependent relaxations during contractions evoked by 5-hydroxytryptamine. The order of relative potency of the agonists was ACh greater than carbachol = oxotremorine in the prehypertensive SHR and Wistar Kyoto rats (WKY). Schild plot data for muscarinic cholinoceptor antagonists obtained with carbachol or oxotremorine as agonist indicated that the arteries of prehypertensive SHR and WKY possessed M3 cholinoceptors mediating relaxation. The relaxation responses of the prehypertensive SHR and WKY arteries to ATP were inhibited by reactive blue 2 but not altered after P2x purinoceptors had been desensitized by alpha,beta-methylene ATP, which suggests that the arteries possessed P2y purinoceptors mediating relaxation. The responses of the femoral and mesenteric arteries from prehypertensive SHR to ACh, carbachol and ATP were similar to those of WKY arteries, although the response of the prehypertensive SHR artery to oxotremorine was significantly increased compared to that of the WKY artery. The results suggest that M3 cholinoceptor- and P2y purinoceptor-mediated relaxations are not changed in prehypertensive SHR arteries as compared to those in WKY arteries.
Fujimoto
S
S
Department of Pharmacology, Nagoya City University Medical School, Japan.
Matsuda
T
T
D000109:Acetylcholine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001158:Arteries / Q000502:physiology; D002217:Carbachol / Q000494:pharmacology; D018680:Cholinergic Antagonists; D004730:Endothelium, Vascular / Q000502:physiology; D005263:Femoral Artery / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D010095:Oxotremorine / Q000494:pharmacology; D010276:Parasympatholytics / Q000494:pharmacology; D058914:Purinergic Antagonists; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D011950:Receptors, Cholinergic / Q000502:physiology*; D011983:Receptors, Purinergic / Q000502:physiology*
D018680:Cholinergic Antagonists; D010276:Parasympatholytics; D058914:Purinergic Antagonists; D011950:Receptors, Cholinergic; D011983:Receptors, Purinergic; D010095:Oxotremorine; D000255:Adenosine Triphosphate; D002217:Carbachol; D000109:Acetylcholine