Vasodilator neurons supplying skin and skeletal muscle of the limbs

Three types of neural vasodilator responses can be identified in the vascular beds of limbs. The first is almost certainly cholinergic, is restricted to precapillary resistance vessels in skeletal muscle, and appears to be activated during emotionally-oriented arousal. The second is non-cholinergic, is attenuated by histamine H1-receptor antagonists, and occurs in both skeletal muscle and skin. This response may also be evoked by emotional stimuli. The third response is localized to arteriovenous shunts in the digits, and is generally insensitive to both anticholinergic and antihistaminic drugs. It is probably implicated in thermoregulatory control, and may mediate cold vasodilation.