| Abstract: | The effects of gonadal steroids on glutamate-mediated pelvic nerve-to-urethra reflex (PUR) plasticity were investigated in rats, which received a sham operation (Sham), ovariectomy (OVX), or ovariectomy with daily supplemental estrogen (50 .mu.g/kg, OVX+E2). The magnitude of the repetitive stimulation (RS, 1 Hz)-induced potentiation in PUR activity decreased significantly in the OVX group when compared with the Sham groups (18.09+-3.91 and 7.40+-1.03 spikes/stimulation inSham and OVX group; respectively, P < 0.01, n = 21). Supplemental estrogen (OVX+E2, 12.60 +- 1.49 spikes/stimulation) significantly reversed the decrease in RS-induced PUR potentiation caused by OVX (P < 0.01, n = 21). The magnitude of the RSinduced potentiation in PUR activity decreased significantly after intrathecal 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo (F) quinoxaline [(20 .mu.M, 10 .mu.l), from 18.09 +- 3.91 to 10.40 +- 0.81, from 7.40 +- 1.03 to 3.20 +- 0.94, and from 12.60 +- 1.49 to 8.06 +- 0.32 spikes/stimulation in Sham, OVX, and OVX+E2, respectively, P<0.01, n=18] and D-2-amino-5-phosphonoraleric acid [(100.mu.M, 10.mu.l), from 18.09+-3.91 to 1.04+-0.12, from 7.40+-1.03 to 1.06 +- 0.22, and from 12.60 +- 1.49 to 0.98 +- 0.25 spikes/ stimulation in Sham, OVX, and OVX+E2, respectively, P < 0.01, n = 18]. In addition, potentiation in PUR activities was induced by intrathecal L-glutamate (0.1 mM, 10 .mu.l, from 1.04 +- 0.02 to 21.60 +- 0.93, from 1.10 +- 0.06 to 8.40 +- 1.50, and from 1.03+-0.03 to 18.04+-0.84 spikes/stimulation in Sham, OVX, and OVX+E2, respectively, P < 0.01, n = 18) and N-methyl-Daspartic acid (0.1 mM, 10 .mu.l, from 1.04 +- 0.02 to 14.80 +- 0.97, from 1.10 +- 0.06 to 4.60 +- 0.48, and from 1.03 +- 0.03 to 9.09 +- 0.63 spikes/stimulation in Sham, OVX, and OVX+E2); N-methyl- D-aspartic acid-mediated PUR plasticity in female rats and may contribute to alterations in urinary dysfunction after menopause. |
