» Articles » PMID: 1674362

Coronary Vascular Responses to Nicotine in the Anaesthetized Dog

Overview
Specialty Pharmacology
Date 1991 Jan 1
PMID 1674362
Authors
Affiliations
Soon will be listed here.
Abstract

The effect of the intra-coronary (i.c.) injection of nicotine on large coronary artery diameter and coronary blood flow was examined in anaesthetized dogs. In sixteen untreated dogs nicotine (20 micrograms i.c.) had a biphasic effect on arterial pressure (initial increase, 7 +/- 2 mmHg; secondary decrease, -8 +/- 3 mmHg) which was accompanied by small and variable effects on heart rate and an increase in LV dP/dt. Nicotine increased large coronary artery diameter by 5.8 +/- 0.8% but had a biphasic effect on coronary blood flow (initial increase, 41 +/- 7 ml/min; secondary decrease, -10 +/- 2 ml/min). Bilateral vagotomy or muscarinic receptor blockade with atropine (0.1 mg/kg i.v.) did not significantly affect the nicotine-induced changes in coronary artery diameter or coronary blood flow. The additional antagonism of beta-adrenoceptors with propranolol (1 mg/kg i.v.) abolished the effect of nicotine in coronary artery diameter (delta CD = 0.2 +/- 0.2%) and the initial increase in coronary blood flow (delta CBF = 1 +/- 1 ml/min) but enhanced the secondary decrease in flow (delta CBF = -25 +/- 3 ml/min). The nicotine-induced decrease in coronary blood flow observed after muscarinic and beta-adrenoceptor blockade was attenuated by antagonism of alpha 1-adrenoceptors with prazosin (10 micrograms/kg i.c., delta CBF = -15 +/- 3 ml/min) and abolished after additional antagonism of alpha 2-adrenoceptors with idazoxan (50 micrograms/kg i.c., delta CBF = -2 +/- 1 ml/min). These results indicate that in the anaesthetized dog intra-coronary injection of nicotine results in beta-adrenoceptor mediated dilatation of both large and small coronary arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

References
1.
Crystal G, Downey H, BASHOUR F . Myocardial oxygen consumption and blood flow during nicotine infusion: effect of combined alpha- and beta-adrenergic blockade. J Cardiovasc Pharmacol. 1981; 3(2):317-27. DOI: 10.1097/00005344-198103000-00010. View

2.
Molenaar P, Jones C, McMartin L, Summers R . Autoradiographic localization and densitometric analysis of beta-1 and beta-2 adrenoceptors in the canine left anterior descending coronary artery. J Pharmacol Exp Ther. 1988; 246(1):384-93. View

3.
Woodman O . The role of alpha 1- and alpha 2-adrenoceptors in the coronary vasoconstrictor responses to neuronally released and exogenous noradrenaline in the dog. Naunyn Schmiedebergs Arch Pharmacol. 1987; 336(2):161-8. DOI: 10.1007/BF00165800. View

4.
Downey H, Williams Jr A, Yonekura S, Watanabe N, Lawrence M . Dominant role of circulating catecholamines in the myocardial contractile response to intravenous nicotine. J Cardiovasc Pharmacol. 1988; 12(1):58-64. DOI: 10.1097/00005344-198807000-00008. View

5.
Hashimoto K, Igarashi S, UEI I, Kumakura S . CAROTID CHEMORECEPTOR REFLEX EFFECTS ON CORONARY FLOW AND HEART RATE. Am J Physiol. 1964; 206:536-40. DOI: 10.1152/ajplegacy.1964.206.3.536. View