Harrell L E, Kolasa K, Parsons D S, Ayyagari V
Department of Neurology, Veterans Administration Medical Center, Birmingham, AL, USA.
Brain Res. 1995 Apr 10;676(2):386-93. doi: 10.1016/0006-8993(95)00070-7.
Following cholinergic denervation of the hippocampus by medial septal lesions, and unusual neuronal reorganization occurs, in which peripheral sympathetic fibers, originating from the superior cervical ganglia, grow into the hippocampus. Previously, we have found that both hippocampal sympathetic ingrowth (HSI) and cholinergic denervation (CD), alone, altered the total number and affinity of muscarinic cholinergic receptors (mAChR). In this study, we utilized the muscarinic antagonist [3H]Pirenzepine, in combination with membrane radioligand binding techniques, to determine the effects of HSI and CD on hippocampal M1 and M1 + M3 mAChR subtypes, 4 weeks after MS lesions. In both the dorsal and ventral hippocampus, HSI was found to markedly diminish the number of M1 AChRs, while CD was found to increase the number of M1 AChRs. Neither treatment affected the affinity of the M1 AChR. However, when M1 + M3 binding was assessed, CD was found to decrease the affinity in both hippocampal regions, without altering the number of receptors. Neither affinity nor number of M1 + M3 receptors was altered by HSI. The results of this study suggest that both cholinergic denervation and hippocampal sympathetic ingrowth uniquely affect hippocampal muscarinic receptors.
通过内侧隔区损伤对海马进行胆碱能去神经支配后，会发生一种不寻常的神经元重组，即源自颈上神经节的外周交感神经纤维长入海马。此前，我们发现海马交感神经长入（HSI）和胆碱能去神经支配（CD）单独都会改变毒蕈碱胆碱能受体（mAChR）的总数和亲和力。在本研究中，我们在进行内侧隔区损伤4周后，利用毒蕈碱拮抗剂[3H]哌仑西平结合膜放射配体结合技术，来确定HSI和CD对海马M1以及M1 + M3 mAChR亚型的影响。在背侧和腹侧海马中，发现HSI会显著减少M1 AChRs的数量，而CD会增加M1 AChRs的数量。两种处理均未影响M1 AChR的亲和力。然而，当评估M1 + M3结合时，发现CD会降低两个海马区域的亲和力，但不改变受体数量。HSI既未改变M1 + M3受体的亲和力也未改变其数量。本研究结果表明，胆碱能去神经支配和海马交感神经长入均独特地影响海马毒蕈碱受体。
