Article

Histamine and the heart

Canadian Journal of Physiology and Pharmacology (Impact Factor: 1.77). 07/1984; 62(6):720-6. DOI: 10.1139/y84-119
Source: PubMed
ABSTRACT
Histamine has been known as a cardiac stimulant for over 70 years. Work in our laboratory over the past decade has established that histamine receptors exist in the hearts of various species. The type of histamine receptor varies not only between species but also in the various regions of the heart. In the guinea pig heart H1 receptors are found in left atria and ventricles while H2 receptors are found in right atria and are the predominant histamine receptor in the ventricles. Rabbit atria contain both H1 and H2 receptors while the ventricles appear to possess only H1. Rat and cat heart do not seem to have histamine receptors and the positive inotropic and chronotropic effects elicited by histamine in cardiac preparations of these species are due to the release of noradrenaline. Dog heart contains H1 receptors while human heart has H2 receptors. In all cases H2 receptors are associated with adenylate cyclase and stimulation of such receptors results in an increase in cyclic AMP levels. H1 receptors are not associated with cyclic nucleotides in the heart. There are certain similarities between beta-adrenergic and H2-histaminergic receptors as well as between alpha-adrenergic and H1-histaminergic receptors. Stimulation of either histamine receptor must result in an increase in the free calcium ion concentration in the cardiac cell but the mechanisms involved are obviously different.

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Available from: John H McNeill, Aug 11, 2015
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    • "Histamine administration has also been associated with a broad range of observations after administration or endogenous release. Literature on histamine administration in humans or rats demonstrates positive inotropic and chronotropic effects along with varying degrees of vasoactive stimulus [23] . However, rat heart is reported not to have histamine receptors, possibly biasing its use as a valid animal model for this research. "
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    • "Sensitivity of the current in rat atrial cells to protein kinase A (PKA)-stimulation was verified, since a reversible increase in I Ca by 91 F 28% (n = 8), in response to 10 AM isoproterenol was recorded (Fig. 1A,C). Our experiments clearly suggest that functional expression of H 2 -R in atrial myocytes is absent or marginal, in line with previous studies in rat and guinea pig heart (for review see Refs. [1,2]). In reporter-positive atrial myocytes transfected with the H 2 -R encoding pcDNA3.1 vector, exposure to His (10 AM) resulted in a reversible augmentation of I Ca by 70 F 19% (n = 8) (Fig. 1B,C). "
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    [Show abstract] [Hide abstract] ABSTRACT: Histamine has been shown to have both positive inotropic and chronotropic effects. To evaluate the chronotropic effects, spontaneously contracting monolayers of cultured rat myocardial cells were treated with histamine, 10(-7) M-10(-4) M. This resulted in a dose-dependent increase in contraction frequency reaching a maximum in 10(-5) M histamine. Contraction frequency (mean +/- SEM) increased from a control of 121 +/- 5 contractions per minute to 153 +/- 4.5, 181 +/- 9, 212 +/- 4, and 216 +/- 1 in 10(-7) M, 10(-6) M, 10(-5) M, and 10(-4) M histamine, respectively (for each n = 10, p less than 0.001). The effect was time-dependent, taking 30 minutes to develop fully. Changes in contraction frequency were accompanied by parallel dose- and time-dependent increases in the verapamil-sensitive sodium influx. Verapamil-sensitive sodium influx (pmol/cm2/sec) increased from a control of 10.45 +/- 1.44 (mean +/- SEM) to 24.34 +/- 2.41 and 32.57 +/- 2.35 at 10- and 30-minute treatment with 10(-6) M histamine (n = 5, p less than 0.001). These data fit the previously described relation between verapamil-sensitive sodium influx and contraction frequency in these cells. Cimetidine (10(-4) M) but not diphenhydramine (10(-4) M) abolished both the contraction frequency and sodium influx response to histamine. Subsequent studies showed a dose- and time-dependent elevation of cyclic adenosine monophosphate (cAMP) with histamine treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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