Module 6: Figure ventricular cyclic AMP microdomains
Microdomains of cyclic AMP in ventricular cardiac cells.
This three-dimensional drawing illustrates the relationship of the T-tubule, the junctional sarcoplasmic reticulum (SR), the free SR and the contractile myofibril. The T-tubule has β-adrenergic receptors on the surface facing the junctional SR and on the surface facing the free SR. Both groups of receptors appear to be capable of setting up separate microdomains of cyclic AMP (shown in yellow).