Regional differences in vascular responses in the human uterus

Abstract
Summary. Tissue specimens from the fundus, isthmus and distal cervix were obtained from 14 women at hysterectomy at various phases of the menstrual cycle. Ring preparations of small intramyomctrial and intracervical arteries were dissected and mounted in organ baths; isometric tension was recorded and responses to contractile agents were studied. The amplitude of responses to K+ (124mmol/l) of the vessel preparations ranked fundus isthmus > cervix. While similar pD2 values for noradrenaline (NA) were found, the Emax values ranked cervix isthmus fundus (cervix > fundus). The pD2 values for arginine-vasopressin (AVP) showed minor differences, while the Emax values for this peptide ranked fundus isthmus cervix (fundus > cervix). Arteries from the fundus and isthmus displayed weak, inconsistent contractile responses to prostaglandin F, but more pronounced contractions were induced by this prostanoid in arterial preparations from the distal cervix. The results suggest regional differences in vascular mechanical responses to endogenous vasoactive agents in the human uterus.