利血平和丘脑下部促黄体素释放激素类似物(LHRH-A)对大鳞副泥鳅促性腺激素细胞的分泌活动和排卵的促进作用

EFFECTS OF RESERPINE AND LHRH-A ON SECRETORY ACTIVITY OF GONADOTROPS AND OVULATION IN FEMALE LOACH PARAMISGURNUS DABRYANUS

利血平能使神经分泌细胞的儿茶酚胺贮存量减少甚至消耗殆尽,导致多巴胺作为GRIF的作用减弱,从而显著增强LHRH-A促进GtH分泌和诱导排卵的效应。对大鳞副泥鳅,利血平和LHRH-A同时注射或者利血平比LHRH-A提前3小时注射,都能激活GtH细胞,显著增强其分泌活动并诱导排卵。利血平的最低有效剂量为1—5微克/克体重。利血平(25微克/克体重)+LHRH-A(0.05微克/克体重)的催产效果和多巴胺拮抗物pimozide(1微克/克体重)+LHRH-A(0.05微克/克体重)的催产效果一样,排卵率都达到了100％。

The tranquilizing drug reserpine (3,4,5-trimethoxybenzoic acid ester), a depleter of nenrotransmitter stores causing depletion of the catecholamine storage of catecholami-nergic neurosecretory cell, decreased the inhibitory effect of dopamine on the release of GtH, thus, greatly potentiated the effects of LHEH-A on GtH secretion and ovulation.Intraperitoneal injection of high dose reserpine (25-100 μg/g body weight) slightly activated gonadotrops with little degranulation, but did not induce ovulation. However, 24 h after reserpine was injected 3 h prior to or with the single injection of low dose LHEH-A (0.1-0.005 μg/g body weight), most gonadotrops appeared degranulation and ultrastructural features of enhanced-synthesis and release of their secretory products. At the same time, many fish ovulated and a high rate of occurrence of ovulation (66.7-90%) was observed, significantly greater than that in groups injected with LHBH-A+vehicle (16.7-20%). The effective dosage of reserpine is 1-5 μg/g body weight. A high rate of occurrence of ovulation (100%) was observed within 24 h when reserpine 25 μg+LHEH-A 0.05 μg/g body weight or dopamine receptor antagonist, pimozide 1 μg+LHEH-A 0.05 μg/g body weight was injected, significantly greater than that in group injected with carp pituitary (62%). These results showed that in spite of the action mechanisms of reserpine are different from pimozide, due to the same action of lowering the effect of dopamine acts as GEIF, both of them can potentiate the effects of LHEH-A on GtH secretion and ovulation significantly.