Differential alpha- and beta-adrenergic responsiveness of beating rat heart myocytes after stationary and non-stationary cultivation.
Spontaneously beating myocytes from the heart ventricles of 1 to 4-day old rats were maintained for 8 days in stationary or in rocker culture under otherwise identical conditions and exposed to phenylephrine and isoproterenol for comparison of their positive chronotropic responses to alpha and to beta-adrenoceptor stimulation, respectively. The heart myocytes in rocked culture were more sensitive to phenylephrine and less sensitive to isoproterenol than were the myocytes in stationary culture and they also displayed a greater maximal response to the alpha-agonist. Addition of 1 mM L(+)-lactate to the rocker cultures abolished alpha-adrenergic responsiveness in one third of the cases while persistently increasing beta-adrenergic sensitivity.
D000818:Animals; D002478:Cells, Cultured; D003584:Cytological Techniques; D006321:Heart / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000166:cytology; D010656:Phenylephrine / Q000494:pharmacology*; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D011943:Receptors, Adrenergic, beta / Q000187:drug effects
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D010656:Phenylephrine; D007545:Isoproterenol