Presynaptic autoregulation of norepinephrine release from the sympathetic nerve fibers in the pineal gland of the domestic pig. Pharmacological characterization of alpha(2)adrenoceptors mediating this process.
BACKGROUND: Norepinephrine is the main neurotransmitter controlling melatonin secretion in the mammalian pineal gland. Presynaptic autoregulation of norepinephrine release from the sympathetic nerve fibers in the pineal gland is poorly known.
METHODS: Uptake and depolarization-evoked release of (3)H-norepinephrin.....