Goldstein B D, Ibrahim N A
Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta 30912-2300.
Neuropharmacology. 1992 Jan;31(1):43-8. doi: 10.1016/0028-3908(92)90159-m.
The purpose of this study was to determine which inhibitory pathway(s) mediate the alterations in the monosynaptic (MSR) and polysynaptic (PSR) reflexes after two different doses of physostigmine. It was found previously that 0.8 mg/kg physostigmine facilitated the MSR and 2.0 mg/kg initially depressed and then facilitated the MSR. Both doses facilitated the PSR. In this study, the animals were pretreated with either strychnine (0.1 mg/kg) or bicuculline (0.5 mg/kg), prior to the administration of either dose of physostigmine. It was found that both strychnine and bicuculline blocked the facilitation produced by the small dose of physostigmine, while bicuculline alone blocked the depression of the MSR produced by the large dose of physostigmine. Strychnine partially blocked the effects of both doses of physostigmine on the PSR, while bicuculline only partially blocked the effects of the small dose of physostigmine. These data suggest that the depression of the MSR was the result of a GABA-mediated pathway, while the facilitation of MSR involved both glycine and GABA.
本研究的目的是确定在给予两种不同剂量的毒扁豆碱后，哪些抑制性通路介导了单突触反射（MSR）和多突触反射（PSR）的改变。先前发现，0.8mg/kg毒扁豆碱可促进MSR，而2.0mg/kg毒扁豆碱最初会抑制然后促进MSR。两种剂量均能促进PSR。在本研究中，在给予任一剂量的毒扁豆碱之前，先用士的宁（0.1mg/kg）或荷包牡丹碱（0.5mg/kg）对动物进行预处理。结果发现，士的宁和荷包牡丹碱均能阻断小剂量毒扁豆碱产生的促进作用，而仅荷包牡丹碱能阻断大剂量毒扁豆碱引起的MSR抑制。士的宁部分阻断了两种剂量毒扁豆碱对PSR的作用，而荷包牡丹碱仅部分阻断了小剂量毒扁豆碱的作用。这些数据表明，MSR的抑制是由GABA介导的通路所致，而MSR的促进则涉及甘氨酸和GABA两者。
