The involvement of nitric oxide on the adenosine A(2) receptor-induced cardiovascular inhibitory responses in the posterior hypothalamus of rats.
This study was performed to investigate the putative relationship between nitric oxide (NO) and adenosine A(2) receptors on central cardiovascular regulation in the posterior hypothalamus of rats. Posterior hypothalamic injection of drugs was performed in anesthetized, artificially ventilated male Sprague-Dawley rats. Injection of adenosine A(2) receptor agonist 5'-(N-cyclopropyl)-carboxamidoadenosine (CPCA; 1, 2 and 5 nmol) produced a dose-dependent decrease of blood pressure and heart rate. Pretreatment with adenosine A(2) receptor antagonist 3,7-dimethyl-1-propargylxanthine (10 nmol) blocked the depressor and bradycardiac effects of CPCA (5 nmol). Pretreatment with soluble guanylate cyclase inhibitor LY-83,583 (5 nmol) attenuated the depressor and bradycardiac effects of CPCA (5 nmol). In addition, pretreatment with NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (40 nmol) attenuated the depressor and bradycardiac responses of CPCA (5 nmol). These results suggest that adenosine A(2) receptor in the posterior hypothalamus plays an inhibitory role in central cardiovascular regulation and that NO participates in the inhibitory response induced by adenosine A(2) receptor stimulation in the posterior hypothalamus.
Song
Man Sung
MS
Department of Pharmacology, College of Medicine, Hanyang University, 17 Haengdang-Dong, Sungdong-Ku, Seoul 133-791, South Korea.
Shin
Kyoung Ah
KA
Kang
Ju Seop
JS
Lee
Chang Ho
CH
Shin
In Chul
IC
Lee
Soo-jin
SJ
Koh
Hyun Chul
HC
D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000634:Aminoquinolines / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D007031:Hypothalamus / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D051381:Rats; D017207:Rats, Sprague-Dawley; D018047:Receptors, Purinergic P1 / Q000502:physiology*; D013805:Theobromine / Q000031:analogs & derivatives* / Q000494:pharmacology
D000634:Aminoquinolines; D004791:Enzyme Inhibitors; D058906:Purinergic P1 Receptor Agonists; D058915:Purinergic P1 Receptor Antagonists; D018047:Receptors, Purinergic P1; D009569:Nitric Oxide; C024311:N-cyclopropyl adenosine-5'-carboxamide; C057837:3,7-dimethyl-1-propargylxanthine; C041715:6-anilino-5,8-quinolinedione; D000241:Adenosine; D013805:Theobromine; D019331:NG-Nitroarginine Methyl Ester