Final answer:
Alpha-2 receptors at the nerve terminal control NE release by functioning as an auto-inhibitory feedback mechanism, leading to a reduction in cAMP levels and NE release.
Step-by-step explanation:
The adrenoreceptors that control norepinephrine (NE) release from the nerve terminal are the alpha-2 receptors. These receptors, part of the adrenergic receptor system, play a role in the negative feedback mechanism that inhibits further neurotransmitter release. The activation of alpha-2 receptors by norepinephrine leads to a decrease in cAMP levels, which in turn reduces the release of NE, hence functioning as an auto-inhibitory feedback mechanism.
Moreover, it's important to recognize that the adrenergic receptor system includes both alpha and beta receptors, like alpha-1, beta-1, and beta-2 receptors, which are involved in various physiological responses but the specific receptors involved in inhibiting NE release are alpha-2.