Effects of XXXX on sympathetic excitation of A delta mechanical nociceptors.

@entity95 @entity128 @entity7183 @entity158 @entity1063
1. The effects of sympathetic stimulation and close arterial injection of @entity1063 were tested on cutaneous myelinated-fiber (A delta) mechanical nociceptors [high-threshold mechanoreceptors-(MyHTMs)] from normal and from partially transsected nerves. 2. Neither sympathetic stimulation nor close arterial injection of @entity1063 (200 ng) excited MyHTMs (18) recorded from the uninjured great auricular nerve of adult @entity95 . 3. MyHTMs (58) conducting across the site of partial cut lesions, made 2 to 28 days previously, had threshold and responsiveness to mechanical stimuli, receptive field organization, and absence of background discharge typical of such elements in normal nerve. 4. Four MyHTMs recorded from the injured nerves were excited by sympathetic stimulation and/or @entity1063 injection but only one gave more than two impulses within 60 s to either form of stimulation. 5. The meagerness of the sympathetic and adrenergic excitation of MyHTMs after @entity128 contrasts with that observed under similar conditions for @entity7183 polymodal nociceptors. Therefore, induction of adrenergic responsiveness in nociceptors after partial denervation in cutaneous MyHTMs appears to be less important for mechanisms related to pathogenic @entity158 than alterations in certain @entity7183 nociceptors.
