QUANTITATIVE-ANALYSIS OF CUTANEOUS CALCITONIN-GENE-RELATED PEPTIDE CONTENT IN RESPONSE TO ACUTE CUTANEOUS MECHANICAL OR THERMAL STIMULI ANDIMMOBILIZATION-INDUCED STRESS IN RATS

The effects of various stimuli on restricted skin areas or immobilizat ion-induced stress on the calcitonin gene-related peptide (CGRP) conte nt in rat skin were examined by radioimmunoassay (RIA) and immunohisto chemistry. Various stimuli were delivered to the shaven skin of the me dial thigh by pinching, brushing, or contact with a glass tube contain ing hot (50 degrees C) or ice-water for 2 min. To induce immobilizatio n stress, animals were placed in the prone position and wrapped with f lexible wire gauze at room temperature. The cutaneous CGRP content det ermined by RIA as well as the number of CGRP-immunoreactive nerve fibe rs of the skin were significantly higher at sites stimulated by pinchi ng or ice-water compared to non-stimulated areas within the same anima ls. However, after brushing, hot water stimulation or any period (2 mi n, 30 min, 2 h, 6 h, or 3 days x 6 h) of immobilization stress, no dif ferences in cutaneous CGRP content were observed. Plasma corticosteron e levels increased after immobilization stress of 30 min or greater, b ut plasma CGRP level did not change after any period of immobilization stress. These data suggest that some forms of cutaneous stimulation c ause a rapid rise in CGRP content in the skin, while emotional stress does not influence the cutaneous CGRP content.