期刊
AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL
卷 105, 期 1, 页码 35-44出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/S1566-0702(03)00024-9
关键词
tetanically induced LTP; sympathetic preganglionic and postganglionic neurons; autonomic neurons; phorbol ester; long-term potentiation; protein kinase C; synaptic modulation; rat SCG; autonomic ganglia; intracellular mediators; second messengers; cell signaling
资金
- NINDS NIH HHS [NS27319] Funding Source: Medline
The long-term potentiation of nicotinic synaptic transmission induced by both active phorbol ester (4beta-phorbol-12,13-dibutyrate, PdBu) and tetanic trains of preganglionic stimulation was studied in single neurons of the superior cervical ganglion (SCG) of the rat using intracellular recording techniques. PdBu significantly increased the mean amplitude of both the unitary evoked fast excitatory postsynaptic potentials (EPSPs) and the fast excitatory postsynaptic currents (EPSCs) to 17.0 +/- 3.3 mV (control 8.4 +/- 1.9 mV, n = 5) and 2.8 +/- 0.4 nA (control 0.8 +/- 0.1 nA, n = 10), respectively. There was no significant change in either the resting membrane potential, input resistance, or the threshold for the initiation of an action potential. The response to exogenously applied acetylcholine (ACh) was also not changed following exposure to PdBu. In low-calcium, high-magnesium solutions, PdBu significantly increased the quantal content of EPSPs approximately threefold from a control of 0.9 +/- 0.2 (n = 5) to 2.6 +/- 0.6 (n = 5). The quantal content of EPSCs was also increased to 1.3 +/- 0.2 (control 0.5 +/- 0.1, n = 10). PdBu increased the frequency of miniature EPSPs (mEPSPs) to 196 +/- 47% (n = 6) of control, while the amplitude, rise time, rate of rise, and decay of mEPSPs were not significantly changed. Tetanic stimulation significantly increased the amplitude of the unitary synaptic EPSPs and EPSCs without significantly changing the resting membrane potential, input resistance, threshold for initiation of an action potential, or the response to exogenously applied ACh. Tetanic stimulation significantly increased quantal content of EPSPs and EPSCs threefold. The results obtained with tetanically induced LTP are similar to the results obtained with phorbol ester-induced LTP in these ganglion neurons. These results suggest that both tetanically induced and phorbol ester-induced LTP, in the rat, share similar mechanisms which involve, at least in part, activation of PKC-dependent mechanisms to increase quantal release from sympathetic preganglionic axon terminals. (C) 2003 Elsevier Science B.V. All rights reserved.
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