title: Lack of nitric oxide sensitivity of carotid sinus baroreceptors activated by normal blood pressure stimuli in cats.
abstract: We examined the effects of inhibition of nitric oxide (NO) synthesis and local administration of NO-donors on baroreceptor activity in anaesthetized cats. Baroreceptor activity was assessed by measuring changes in the pulse synchronous carotid sinus nerve discharge in a modified blind sack preparation. Within physiological mean arterial blood pressure (BP) ranges (BP = 70-150 mmHg), neither abluminal (in a pool around the carotid sinus, n = 15) nor intravascular (via the A. lingualis, n = 10) administration of the NO-synthase inhibitor N(G) nitro-L-arginine (L-NNA, 30 mu M) significantly modulated baroreceptor activity. The NO donors S-nitroso-N-acetylpenicillamine, sodium nitroprusside and glyceryltrinitrate caused significant decreases in baroreceptor activity only when applied intravascularly at concentrations > or = 100 mu M. In contrast, prostacyclin (1 mu M, n = 5) attenuated and indomethacin (10 mu M, n = 5) enhanced baroreceptor activity significantly upon intravascular administration. Baroreceptor activity was also effectively inhibited by gadolinium (Gd(3+), 1 mM). These results suggest that carotid sinus baroreceptor function in cats is rather insensitive to changes in the supply of endogenous or exogenous NO.
authors.affiliation: Physiologisches Institut, Universitat Heidelberg, Germany. zanzing@novsrvl.piol.uni-heidelberg.de
authors.forename: J
authors.initials: J
authors.lastname: Zanzinger
authors.forename: J
authors.initials: J
authors.lastname: Czachurski
authors.forename: H
authors.initials: H
authors.lastname: Seller
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D002346:Carotid Sinus / Q000294:innervation / Q000502:physiology*; D002415:Cats; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004594:Electrophysiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D011464:Epoprostenol / Q000494:pharmacology; D005682:Gadolinium / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D019335:Nitroarginine / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D011311:Pressoreceptors / Q000187:drug effects / Q000503:physiopathology*; D026423:S-Nitroso-N-Acetylpenicillamine; D012680:Sensitivity and Specificity; D013564:Sympathetic Nervous System / Q000502:physiology
chemical_list: D000959:Antihypertensive Agents; D016861:Cyclooxygenase Inhibitors; D004791:Enzyme Inhibitors; D009599:Nitroprusside; D019335:Nitroarginine; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D005682:Gadolinium; D011464:Epoprostenol; D010396:Penicillamine; D007213:Indomethacin