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Streptomycin inhibition of myogenic tone, K + ‐induced force and block of L‐type calcium current in rat cerebral arteries
Author(s) -
Miller A. L.,
Langton P. D.
Publication year - 1998
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1998.793bp.x
Subject(s) - electrical impedance myography , chemistry , isometric exercise , streptomycin , cerebral arteries , biophysics , anatomy , myocyte , endocrinology , medicine , biochemistry , biology , vasodilation , antibiotics
1 Streptomycin has been demonstrated to inhibit mechanosensitive conductances in a wide variety of cell types, including muscle. The action of streptomycin on rat cerebral arteries that exhibit pressure‐induced myogenic response was investigated. 2 Pressure‐induced tone, measured using isobaric myography, in isolated pressurized cerebral arteries was reversibly and concentration‐dependently inhibited by streptomycin with an IC 50 of 2.6 mM. 3 Isometric K + ‐induced force, measured using isometric myography, is supported by voltage‐gated Ca 2+ entry. Streptomycin reversibly and concentration‐dependently inhibited isometric force with an IC 50 of 1.71 mM. 4 Voltage‐gated macroscopic inward Ca 2+ channel currents were recorded from freshly isolated rat basilar myocytes. These were reversibly and concentration‐dependently inhibited by streptomycin with an IC 50 of 1.79 and 0.47 mM when 10 and 1.8 mM CaCl 2 , respectively, was used as the charge carrier. 5 These data suggest that streptomycin inhibits myogenic tone and K + ‐induced isometric force largely by blockade of L‐type, dihydropyridine‐sensitive Ca 2+ channels. In conclusion, streptomycin is not useful in the investigation of stretch‐activated channels which may underlie the myogenic response of rat small cerebral arteries.