PHARMACOLOGY OF THE HUMAN OVARIAN VEIN - RESPONSES TO PUTATIVE NEUROTRANSMITTERS AND ENDOTHELIN-1

Objective An investigation of excitatory vascular responses in the hum an ovarian vein, a blood vessel normally exposed to high concentration s of ovarian steroid hormones and capable of adaptation to circulatory changes associated with reproductive life. Design Pharmacological res ponses of surgical specimens of human ovarian vein to electrical field stimulation of sympathetic nerves, noradrenaline, alpha,beta-methylen e adenosine 5'-triphosphate (alpha,beta-MeATP), endothelin-1 (ET-1), a nd 5-hydroxytryptamine (5-HT) were studied. Comparisons were made betw een in vitro pharmacological responses and the diagnostic category, ag e, smoking status, reproductive history and hormonal status of patient s. Setting Research laboratory. Results Maximal contractile responses in longitudinal preparations, expressed as a percentage of the respons e to potassium chloride 125 mmol1(-1), were 28% (SE 7.2) to electrical field stimulation and 107 % (SE 15.1) to noradrenaline. In ring prepa rations, maximal responses to various agents were: noradrenaline 93 % (SE 10.2); 5-HT 79 % (SE 8.0); alpha,beta-MeATP 48 % (SE 8.4); and ET- 1 87% (SE 10.1). pD(2)(-log EC(50)) values for noradrenaline were 5.82 (SE 0.21) in longitudinal preparations and 5.65 (SE 0.10) in ring pre parations; for ET-1 in ring preparations these values were 7.88 (SE 0. 74). Responses to sympathetic nerve stimulation were attenuated by the adrenoceptor antagonist phentolamine; any residual responses were blo cked by desensitisation of P-2-purinoceptors with alpha,beta-MeATP or the addition of suramin, indicating that noradrenaline and adenosine 5 '-triphosphate may be co-transmitters in these nerves. pD(2) values fo r 5-HT were 5.97 (SE 0.12) in specimens from unsterilised patients (n = 19) compared with 5.20 (SE 0.24) in specimens from those who had pre viously undergone sterilisation (n = 6) (P < 0.05). No other relation between clinical characteristics and pharmacological responses were de tected and, in particular, there were no apparent changes associated w ith ageing or hormonal status. Conclusions Three main conclusions may be drawn from this study: (1) adenosine 5'-triphosphate is a co-transm itter in sympathetic nerves in the human ovarian vein; (2) tubal steri lisation affects vascular responsiveness to 5-HT; and (3) ovarian ster oid hormones are likely to influence sympathetic vascular control via effects on catecholamine and adenosine 5'-triphosphate synthesis, stor age, release, degradation or re-uptake, rather than via effects on vas cular smooth muscle receptors.