Krzanowska E K, Bodnar R J
Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
Brain Res. 1999 Mar 6;821(1):224-30. doi: 10.1016/s0006-8993(98)01364-x.
Sex differences have been observed in antinociception following central administration of morphine into either the lateral ventricles or rostral ventromedial medulla (RVM) such that male rats exhibit significantly greater antinociception than female rats. The present study examined whether sex and adult gonadectomy differences were observed in morphine-induced (1-10 micrograms) antinociception elicited from the ventrolateral periaqueductal gray (vlPAG) on two nociceptive measures. Both sham-operated (ED50=1.20-1.60 microgram) and castrated (ED50=1.08-1.09 micrograms) male rats displayed significantly greater magnitudes and potencies of morphine-induced antinociception on both tests than female rats. Sham-operated female rats tested during the estrous phase (ED50=>50 micrograms) were significantly less sensitive to morphine than ovariectomized female rats (ED50=1.98-2. 51 micrograms). Thus, the vlPAG, a site sensitive to interactions between estradiol-containing hypothalamic loci and opioid peptides, elicits morphine-induced antinociception which is sensitive to sex differences and adult gonadectomy.
在向侧脑室或延髓头端腹内侧（RVM）中枢给予吗啡后，已观察到雄性和雌性大鼠在抗伤害感受方面存在性别差异，即雄性大鼠表现出比雌性大鼠显著更强的抗伤害感受。本研究考察了在两种伤害感受测量指标上，从腹外侧导水管周围灰质（vlPAG）诱发的吗啡诱导（1 - 10微克）抗伤害感受中，是否存在性别差异以及成年去势差异。在两项测试中，假手术组（半数有效量[ED50]=1.20 - 1.60微克）和去势组（ED50=1.08 - 1.09微克）雄性大鼠的吗啡诱导抗伤害感受的强度和效力均显著高于雌性大鼠。处于发情期的假手术组雌性大鼠（ED50>50微克）对吗啡的敏感性显著低于卵巢切除的雌性大鼠（ED50=1.98 - 2.51微克）。因此，vlPAG作为一个对含雌二醇的下丘脑位点与阿片肽之间相互作用敏感的部位，诱发的吗啡诱导抗伤害感受对性别差异和成年去势敏感。
