Society, in Hiroshima, June 4, 1972. Abstract-Effect of removal of Na from bathing media on the tonus and contractile response to drugs of strips of the rat ileum was investigated. Removal of Na from the bathing media by replacing NaCl with sucrose or choline Cl produced a transient contraction, which was not altered by treatment with atropine. This contraction was attenuated when preparations ...

MA, T. S., AND D. BOSE. Sodium in smooth muscle reluxation. Am. J. Physiol. 232(l): C59-C66, 1977 or Am. J. Physiol.: Cell Physiol. l(1): C59-C66, 1977. -The contraction of guinea-pig taenia coli due to high K+ could not be reversed by washing when Na+ was absent from the medium. Reintroduction of Na+ (7 mM or more) caused relaxation. Similar results were obtained with rat uterus. The effect of...

MA, T. S., AND D. BOSE. Sodium in smooth muscle reluxation. Am. J. Physiol. 232(l): C59-C66, 1977 or Am. J. Physiol.: Cell Physiol. l(1): C59-C66, 1977. -The contraction of guinea-pig taenia coli due to high K+ could not be reversed by washing when Na+ was absent from the medium. Reintroduction of Na+ (7 mM or more) caused relaxation. Similar results were obtained with rat uterus. The effect of...

The contraction of guinea-pig taenia coli due to high K+ could not be reversed by washing when Na+ was absent from the medium. Reintroduction of Na+ (7 mM or more) caused relaxation. Similar results were obtained with rat uterus. The effect of sodium replacement was not due to change in ionic strength because equal or higher osmoles of choline, Ca++, K+, Mn++, or Mg++ had little or no effect. P...

MA, T. S., AND D. BOSE. Sodium in smooth muscle reluxation. Am. J. Physiol. 232(l): C59-C66, 1977 or Am. J. Physiol.: Cell Physiol. l(1): C59-C66, 1977. -The contraction of guinea-pig taenia coli due to high K+ could not be reversed by washing when Na+ was absent from the medium. Reintroduction of Na+ (7 mM or more) caused relaxation. Similar results were obtained with rat uterus. The effect of...

Methods. Changes in isometric tension were recorded in helical strips of the arteries, and the presence of perivascular nerve containing NADPH diaphorase was histochemically demonstrated. Results. Nicotine (10~ M, EOA and IOA) and transmural electrical stimulation (5 Hz, EOA) produced a slight or no contraction followed by a moderate relaxation in the strips contracted with prostaglandin F2a. T...

Proper contractile function of the heart depends on intact excitation–contraction processes and ion homeostasis of the myocytes. The 21 21 1 Ca ion activates contraction through its binding to troponin C. However, Ca homeostasis is tightly linked to Na regulation because 21 1 21 21 the primary mechanism for Ca efflux in cardiac myocytes is via electrogenic Na /Ca -exchange. While altered Ca -ho...

Monolayer cultures of myocardial cells were prepared by trypsin dispersion of neonatal rat ventricles. The cells were cultured for 4-5 days by which time a synchronously contracting monolayer of some 1.0 x 10(6) cells per 6-cm diam petri dish had formed. The contraction frequency and Na influx of the cells were unaffected by tetrodotoxin (2 x 10(-5) mg/ml) but both were markedly reduced by the ...

Regulation of the supersensitivity and subsensitivity of the alpha adrenergic (alpha-Ad) system of rat vas deferens cultured under various experimental conditions was investigated. Muscles cultured for 3 days in normal medium (Eagle's MEM) exhibited marked increase in maximal contraction to noradrenaline (NA) and high K+ (154 mM), while muscles cultured with NA (100 microM) were subsensitive to...