Enhanced acetylcholine release from denervated atria: intrinsic neural supersensitivity

Atrial tissue from denervated dog hearts was incubated with [3H]choline. When compared with controls, nicotine released more acetylcholine (ACh) from denervated atria at 10(-5) and 2 x 10(-5) M, but not at 5 x 10(-5) M. In parallel contractility studies using tissue from these same atria, the negative inotropic response to nicotine was enhanced at 5 x 10(-6) and 10(-5) M, but not at 2 x 10(-5) or 5 x 10(-5) M nicotine. These results indicate that denervation (i.e. decentralization) supersensitivity of the intrinsic cardiac nerves of canine hearts is characterized by enhanced release of ACh.