Evidence for the existence of stereoselective presynaptic beta 1-adrenoceptors on noradrenergic and dopaminergic neurons in the rat hypothalamus.

Using high performance liquid chromatography with an electrochemical detector, we examined antagonistic effects of l- and d-acebutolol and atenolol against isoproterenol-induced facilitation of impulse-evoked release of endogenous norepinephrine and dopamine in rat hypothalamic slices. Isoproterenol (10 nM) increased the release of the both catecholamines, and this facilitation was similarly antagonized by 100 nM l-acebutolol and 100 nM atenolol, but was not antagonized by 100 nM d-acebutolol. In conclusion, there exist stereoselective presynaptic beta 1-adrenoceptors on noradrenergic and dopaminergic neurons in the rat hypothalamus.