Pittner H. Effects of midodrine, ST 1059, methoxamine and glycine on spontaneously beating guinea-pig atria.
AGENTS AND ACTIONS 1976;
6:584-8. [PMID:
61715 DOI:
10.1007/bf01971573]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The chronotropic effects of midodrine, glycine (10(-8) to 3.10(-3) M), ST1059 and methoxamine (10(-8) to 10(-3) M) were investigated in the spontaneously beating guinea-pig right atrial preparation. Midodrine and glycine produced a slight, but significant rise in atrial rate over a wide concentration range. The midodrine-induced rise in atrial rate was not influenced by the beta-adrenergic receptor blocking drug propranolol (10(-6) M). The histamine (H2)-receptor blocking drug metiamide (3.10(-5) M) abolished the positive chronotropic actions of both midodrine and glycine. No positive chronotropic effect was seen after the administration of ST 1059 or methoxamine. A decrease in atrial rate was elicited by high concentrations (above 10(-4) to 10(-3) M) of the sympathomimetic agents midodrine, ST 1059, and methoxamine, but not by the amino acid glycine.
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