- 作者: Yoichi Yajiri; Li-Yen Mae Huang
- 作者服務機構: Marine Biomedical Instrtue, Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston, Tex., USA
- 中文摘要: --
- 英文摘要: The effects of endogenous p-opioid ligands, endomor-phins, on Aδ-afferent-evoked excitatory postsynapticcurrents (EPSCs) were studied in substantia gelatinosaneurons in spinal cord slices. Under voltage-clamp con-ditions, endomorphins blocked the evoked EPSCs in adose-dependent manner. To determine if the block re-suited from changes in transmitter release from gluta-matergic synaptic terminals, the opioid actions on minia-ture excitatory postsynaptic currents (mEPSCs) were ex-amined. Endomorphins (1 μM) reduced the frequencybut not the amplitude of mEPSCs, suggesting that endo-morphins directly act on presynaptic terminals. The ef-fects of endomorphins on the unitary (quantal) proper-ties of the evoked EPSCs were also studied. Endomor-phins reduced unitary content without significantlychanging unitary amplitude. These results suggest thatin addition to presynaptic actions on interneurons, endo-morphins also inhibit evoked EPSCs by reducing trans-mitter release from Aδ-afferent terminals.
- 中文關鍵字: --
- 英文關鍵字: --