Noxious and innocuous mechanical cutaneous stimulation increase the sympathetic efferent nerve activity innervating...

Effects of pinching and brushing of the various segmental skin areas (face, ear, neck, forelimb, chest, abdomen, hindlimb) on the activities of the sympathetic efferent nerve innervating the interscapular brown adipose tissue (IBAT) and contributing to its thermogenesis were examined in anesthetized rats. Pinching the face, ear, neck, or forelimb produced significant reflex increases in the efferent nerve activities, whereas pinching the chest, abdomen, or hindlimb did not produce any significant responses. In the case of brushing stimulation, only the stimulation of the ear produced significant increases. These results demonstrated that cutaneous mechanical stimulations at cranial, cervical, and upper thoracic segments were effective in producing reflex increases in the activities of the IBAT sympathetic nerve and that noxious stimulation was more dominant for eliciting the reflex responses.