EN
In the present paper the influence of the rat C-terminal fragment [Tyr°]CGRP(28-37) (Ct-CGRP) was compared with the influences of noradrenaline (NA) and acetylcholine (ACh), respectively on isolated pig uterine artery (UA). It was shown that Ct-CGRP (10 -8 mol/1) caused contraction of UA, similar to NA (10-7 mol/1) action. ACh addition before Ct-CGRP treatment inhibited the action of this peptide. ACh administration after Ct-CGRP pretreatment negated the action of this peptide, whereas Ct-CGRP given before and after NA treatment caused additive contractile reactions of UA. Moreover, it was also shown that susceptibility of UA reaction on Ct-CGRP was higher in the postovulatory phase than in other phases of the oestrous cycle. But the effect of Ct-CGRP addition in NA pretreatment vessels as well as the influence of NA added after Ct-CGRP pretreatment were more marked in the luteal phase than in pre- and postovulatory phases of the cycle. Furthermore it was showed that CGRP (10 -9 mol/1) caused very strong dilatation of UA, equal to the reaction observed after ACh (10-8 mol/1) treatment. We concluded that Ct-CGRP in contrast to the whole molecule of calcitonin gene-related peptide (CGRP) caused vasocontractile activity in the isolated pig uterine artery. This effect was synergistic with NA action and was inhibited by ACh.