Alpha-adrenoceptor-mediated Chronotropic Response: Influence of Temperature and Basal Spontaneous Rate

Overview

Journal Naunyn Schmiedebergs Arch Pharmacol

Specialty Pharmacology

Date 1989 Mar 1

PMID 2542809

Authors

M C Camilion de Hurtado

O A Gende

Affiliations

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Abstract

The chronotropic response to phenylephrine of isolated rat atria was determined at 37 degrees C and 30 degrees C. At both temperatures similar maximal increases in rate were obtained (91 +/- 4 beats/min and 93 +/- 8 beats/min, respectively). Beta-adrenoceptor blockade (10(-6) M propranolol) abolished the chronotropic effect of phenylephrine at 37 degrees C whereas at 30 degrees C a propranolol-resistant chronotropic effect was detected. The propranolol-resistant chronotropic effect of phenylephrine was sensitive to prazosin blockade (10(-6) M) indicating alpha adrenoceptors involvement in the response. At 37 degrees C a propranolol-resistant, prazosin-sensitive effect of phenylephrine could be obtained if basal rate was lowered (by cholinergic stimulation or acidosis) or if extracellular calcium was increased over 1.35 mM. When the chronotropic effect of phenylephrine was compared at similar basal rates, it was greater at 37 degrees C than at 30 degrees C. These results make unlikely the possibility of increases in sensitivity or in density of alpha-adrenoceptors at low temperature. The fact that alpha-adrenoceptor mediated chronotropic response is enhanced at low basal frequencies makes this mechanism a potential safety factor during bradycardia.

References

Broadley K . The effect of temperature upon the responses of isolated cardiac muscle to sympathomimetic amines. Methods Find Exp Clin Pharmacol. 1980; 2(4):181-93. View

Hamakawa H, Shimizu T, Toda N . Interactions of phenylephrine and theophylline in contractility and excitability of isolated rabbit left atria. Jpn J Pharmacol. 1973; 23(3):373-9. DOI: 10.1254/jjp.23.373. View

Benfey B . Cardiac adrenoceptors at low temperature and the adrenoceptor interconversion hypothesis. Br J Pharmacol. 1977; 61(2):167-73. PMC: 1667505. DOI: 10.1111/j.1476-5381.1977.tb08401.x. View

Gende O, Camilion de Hurtado M, Cingolani E . Chronotropic response of isolated atria to acid base alterations. Arch Int Physiol Biochim. 1978; 86(5):997-1009. DOI: 10.3109/13813457809055959. View

Mugelli A, Ledda F, Mantelli L . Frequency dependence of the alpha-adrenoceptor-mediated positive inotropic effect in guinea pig heart. Eur J Pharmacol. 1976; 36(1):215-20. DOI: 10.1016/0014-2999(76)90274-0. View

Harper J . Peritz' F test: basic program of a robust multiple comparison test for statistical analysis of all differences among group means. Comput Biol Med. 1984; 14(4):437-45. DOI: 10.1016/0010-4825(84)90044-1. View

Mackaay A, Bleeker W, Hof T, BOUMAN L . Temperature dependence of the chronotropic actions of calcium: functional inhomogeneity of the rabbit sinus node. J Mol Cell Cardiol. 1980; 12(5):433-43. DOI: 10.1016/0022-2828(80)90001-2. View

Ledda F, Marchetti P, Mugelli A . Studies on the positive inotropic effect of phenylephrine: a comparison with isoprenaline. Br J Pharmacol. 1975; 54(1):83-90. PMC: 1666381. DOI: 10.1111/j.1476-5381.1975.tb07413.x. View

Pedroni P, Mattiazzi A, Cingolani H . [Effect of alpha 1 adrenergic stimulation on myocardial relaxation]. Acta Physiol Pharmacol Latinoam. 1987; 37(4):491-501. View

10.

Wagner J, Reinhardt D . Characterization of the adrenoceptors mediating the positive ino- and chronotropic effect of phenylephrine on isolated atria from guinea pigs and rabbits by means of adrenolytic drugs. Naunyn Schmiedebergs Arch Pharmacol. 1974; 282(3):295-306. DOI: 10.1007/BF00501237. View

11.

Bennett T, Kemp P . Lack of evidence for a temperature-mediated change of adrenoceptor type in the rat heart. Naunyn Schmiedebergs Arch Pharmacol. 1978; 301(3):217-22. DOI: 10.1007/BF00507040. View

12.

Kaumann A . Adrenergic receptors in heart muscle: relations among factors influencing the sensitivity of the cat papillary muscle to catecholamines. J Pharmacol Exp Ther. 1970; 173(2):383-98. View

13.

Benfey B . Cardiac adrenoceptors at low temperature: what is the experimental evidence for the adrenoceptor interconversion hypothesis?. Fed Proc. 1977; 36(12):2575-9. View

14.

TUNG L, Rand M, Louis W . Calcium antagonists inhibit positive chronotropic responses to alpha 1-adrenoceptor activation in rat isolated atria. Eur J Pharmacol. 1987; 133(2):177-84. DOI: 10.1016/0014-2999(87)90148-8. View

15.

Kunos G, Nickerson M . Effects of sympathetic innervation and temperature on the properties of rat heart adrenoceptors. Br J Pharmacol. 1977; 59(4):603-14. PMC: 1667749. DOI: 10.1111/j.1476-5381.1977.tb07728.x. View

16.

BOUMAN L, GERLINGS E, Biersteker P, Bonke F . Pacemaker shift in the sino-atrial node during vagal stimulation. Pflugers Arch. 1968; 302(3):255-67. DOI: 10.1007/BF00586730. View

17.

Endoh M, Hillen B, SCHUMANN H . Influence of temperature and frequency on the positive inotropic action of phenylephrine in the isolated rabbit papillary muscle. Arch Int Pharmacodyn Ther. 1977; 228(2):213-21. View

18.

Marquez M, Eisenschlos C, ARAMENDIA P . Antagonism and supersensitivity to phenylephrine-induced chronotropic responses. Acta Physiol Lat Am. 1983; 33(3):231-42. View

19.

Wagner J, Brodde O . On the presence and distribution of alpha-adrenoceptors in the heart of various mammalian species. Naunyn Schmiedebergs Arch Pharmacol. 1978; 302(3):239-54. DOI: 10.1007/BF00508293. View

20.

Bradley L, Doggrell S . Effects of prazosin, phentolamine and yohimbine on noradrenergic transmission in the rat right ventricle in vitro. J Auton Pharmacol. 1983; 3(1):27-36. DOI: 10.1111/j.1474-8673.1983.tb00494.x. View