ABSTRACT
It is well know n tha t CGRP and ADM are po ten t vasodilators in hum an and an i m al m odels, (see Kadowitz et al, th is vol um e). H ow ever, th e vascu la r ac tio n s o f am ylin are less well understood. It has been repo rted th a t am ylin induces vasodila tor responses in th e rabb it, th e perfused ra t m esenteric vascular bed and kidney o f the rat, and it appears tha t vasodilator responses to am ylin are dependent upon species and vascular bed studied .l'6 In the cat am ylin has significant vasodilator activity in the pu lm o nary vascular bed ,2 b u t no t in the m esen teric and hind lim b vasculature.3,4
A lthough am ylin, CGRP and ADM are structurally related peptides, little is know n about the receptors m ediating responses to these agonists, (see Sm ith et al, Kadowitz et
al, this volum e) It has been reported tha t am ylin a n d C G R P p ro d u ce v a so d ila to r activity tha t is m ediated via the activation o f the CGRPi receptor, since responses were blocked by CG RP8-37 in the isolated per fused m esenteric vascular bed and kidney o f the rat.2,5 A lthough it has been shown that am ylin produces vasodilator responses via CGRPg-37-sensitive receptors in the perfused m esen te ric v ascu la r b ed a n d k id n ey o f the rat, little if any th ing is know n abou t th e effects o f am yling-37 o n v aso d ila to r responses to CGRP and amylin in the m esen teric vasculature o f the ra t.2,5 M oreover, the m e ch a n ism m e d ia tin g th is v a so d ila to r response is n o t know n. T herefore, the p u r p o se o f th e p re s e n t in v e s tig a tio n w as to study the effects o f am ylin on isolated, p recon trac ted resistance vessels from the m esenteric vascular bed o f the ra t and to evaluate the role o f CGRPg-37-and amylin8.37 -sensitive recep tors in m ed ia ting th e re sponses to hum an (h) CGRP and amylin.
