切断面神经后大鼠面神经核内5-HT_2、M_2和α_1-肾上腺素能受体的变化

CHANGES IN THREE TRANSMITTER-BINDING SITES IN THE RAT FACIAL NUCLEUS FOLLOWING AXOTOMY

采用离体定量放射自显影技术，以氚标配体作为标记物，对切断一侧面神经的25只大鼠，分别于手术后1、4、7、21d和2个月定量观察了术侧面神经核内5-HT2、M2、和α1肾上腺素能受体含量的变化．结果显示，在切断面神经后4d，同侧面神经核内上述受体含量较同体对侧（未切断神经侧）面神经核内受体含量明显减少。5－HT2受体减至正常含量的50％，M2受体减至64％，α1肾上腺素能受体减至73％．术后1周时，所测三种受体含量减至最低点，与同体对侧比较分别减至39K、43％和65％。术后3周，三种受体含量开始回升，至术后2个月时，其值分别增至正常含量的84％、74％和86％．以上结果表明，切断面神经可引起面神经核内受体的可塑性变化，这些受体可能由面神经核内运动神经元产生．

Changes in three different transmittet-binding sites (for M2,5-HT2 and alpha l adrenergic receptors) in the facial nucleus of rats were studied using quantitative in vitro receptor autoradiography at varying time intervals(1, 4, 7, 21 days and 2 months) after unilateral facial nerve transection. The image analysis results revealed that 4 days postaxotomy, the receptor density of 5-HT2. M2 and aIpha 1 adrenergic receptors in facial nucleus ipsi1ateral to the sectioned nerve was reduced to 5O%. 64% and 73%,respectiveIy, as compared to the control intact side 100%; 7 days postaxotomy, the receptor density was significantly reduced to 39% (5-HT2). 43% (M2) and 65 % (a1pha 1 ); 3 weeks postaxotomy, the density of three receptors began to increase;at 2 months, the receptor density of 5-HT2, M2 and alpha l receptors in operated side reached 84 %' 76 % and 86 %, respectively.These resuIts indicated that 5-HT2'M2 and alpha l adrenergic receptors are synthesized by the motoneurons 0f facial nuc1eus and their recovery could account for the phenomenon of the plastic regeneration.