@entity4 induced by phospholipases A2 isolated from Crotalus durissus sp. in the XXXX dorsal skin: a role for mast cells and sensory C-fibers.

@entity7782 @entity2951 @entity13631 @entity4 @entity4478 @entity36315 @entity750 @entity112 @entity35 @entity4756
The ability of the phospholipases A(2) (PLA(2)s) from Crotalus durissus cascavella, Crotalus durissus collilineatus and Crotalus durissus terrificus venoms and @entity36315 to increase the vascular permeability in the @entity35 skin as well as the contribution of both mast cells and sensory C-fibers have been investigated in this study. Vascular permeability was measured as the plasma extravascular accumulation at skin sites of intravenously injected 125I-human serum albumin. Intradermal injection of crotalic PLA(2)s (0.05-0.5 microg/site) in the @entity35 skin resulted in dose-dependent increase in plasma extravascular whereas @entity36315 (1 microg/site) failed to affect this response. Co-injection of @entity36315 (1 microg/site) did not modify the increased vascular permeability induced by the PLA(2)s (0.05-0.5 microg/site). Previous treatment (30 min) of the animals with @entity7782 (2 mg/kg, i.p.) markedly reduced PLA(2) (0.5 microg/site)-induced @entity4 . In @entity35 treated neonatally with @entity2951 to deplete neuropeptides, the plasma extravasation induced by all PLA(2)s (0.5 microg/site) was also significantly reduced. Similarly, the @entity4756 NK(1) receptor antagonist @entity13631 (1nmol/site) significantly reduced the PLA(2)-induced @entity4 . In addition, the combination of @entity13631 with @entity7782 further reduced the increased plasma extravasation by PLA(2) from C. d. cascavella venom, but not by PLA(2) from C. d. terrificus and C. d. collilineatus venoms. Our results suggest that increase in skin vascular permeability by crotalic PLA(2)s is mediated by activation of sensory C-fibers culminating in the release of substance P, as well as by activation of mast cells which in turn release @entity4478 such as @entity112 and @entity750 .
