Guinea pig left atrium

If the tertiary pr-MDI and bu-MDI gain access to the interior of the cell to exert their calcium antagonistic actions, it would be predicted that their quaternary ammonium analogues would be inactive due to their exclusion from the intracellular compartment as a result of their inability to cross biological membranes. As predicted, the tertiary, but not the quaternary, MDIs produce a negative inotropic effect on the isolated electrically-driven guinea pig left atrium (42) and inhibit potassium-induced and norepinephrine-induced contractions of the isolated rat aortic strip (43). 

The antiarrhythmic agent rythmol (78a) and its silicon analogue sila-rythmol (78b for the synthesis see Scheme 3) were evaluated on isolated heart preparations of the guinea pig (left atrium and papillary muscle) for their effects on contractility and on refractory... 

Isomer ai Receptor (rabbit aortic strip) Pi Receptor (guinea pig left atrium) P2 Receptor (guinea pig tracheal strip)... 

The extension of cardiac muscle from the left atrium along the walls of the major pulmonary veins at the hilus is most prominent in rodents as in the rat, the mouse, and exceptionally in the guinea-pig (Guieysse-Pelissier 1937). 

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