QUANTIFICATION OF CATS ARTICULAR AFFERENTS CONTAINING CALCITONIN-GENE-RELATED PEPTIDE OR SUBSTANCE-P INNERVATING NORMAL AND ACUTELY INFLAMED KNEE JOINTS

In cats with an acute (32 h) unilateral knee joint inflammation the pr oportion of calcitonin gene-related peptide- (CGRP) and substance P-(S P) immunoreactive articular afferents, retrogradely labelled by Fast B lue (FB), were determined using immunohistochemistry. The proportion o f neurons containing CGRP was significantly higher on the inflamed sid e (52%) than on the contralateral side (39%) and in controls (42%). Ho wever, the proportion of SP-immunoreactive articular perikarya on the inflamed side (26%) did not differ from the contralateral side (24%) a nd the control cats (22%). These data indicate that acute inflammation induces the synthesis of CGRP but not of SP in joint afferents. (C) 1 997 Elsevier Science Ireland Ltd.