INVITRO RESPONSE OF RABBIT UTERO-OVARIAN LIGAMENT TO CATECHOLAMINES

  • 1 January 1976
    • journal article
    • research article
    • Vol. 27  (8) , 957-964
Abstract
The response of the rabbit utero-ovarian ligament to catecholamines was studied in vitro, with contractile activity being recorded isometrically from whole rabbit ligaments obtained under various hormonal conditions. Both the catecholamines norepinephrine (NE) and epinephrine (EPI) produced dose-dependent (10-2 .mu.g/ml threshold; 102 .mu.g/ml maximum) tetanic contractions of rabbit ligament. There was no difference (P < 0.05) between estrous and ovulatory ligaments either in terms of the dose-response curves or maximal force of contraction. Both agonists were 100% antagonized by the .alpha.-blockers, phentolamine and phenoxybenzamine. The .beta.-agonist, isoproterenol, had little effect on ligament tonus but did inhibit spontaneous activity and attenuated the response to both NE and EPI. Propranolol, a .beta.-blocker, slightly (< 10%) potentiated the stimulatory effects of NE and EPI. The utero-ovarian ligament of the rabbit contains predominately .alpha.-stimulatory and possibly weak .beta.-inhibitory receptors analogous to receptors in ovarian and oviductal smooth muscles.