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[Inhibitory effects of propofol on supraoptic nucleus neurons of rat hypothalamus in vitro.] [Article in Chinese]

ZHANG Huan-Huan, WANG Meng-Ya^*

Cell Electrophysiology Laboratory, Wannan Medical College, Wuhu 241002, China

Abstract

To investigate the effects of novel intravenous general anesthetic propofol on membrane electrophysiological characteristics and action potential (AP) of the supraoptic nucleus (SON) neurons and possible ionic mechanisms, intracellular recordings were conducted in SON neurons from the coronal hypothalamic slice preparation of adult male Sprague Dawley (SD) rats. The results showed that bath application of 0.1 mmol/L propofol induced a significant decline in resting potential (P < 0.01), and higher concentrations of propofol (0.3 and 1.0 mmol/L) decreased time constant and slope resistance of cell membrane (P < 0.01). Under the hyperpolarizing current pulses exceeding 0.5 nA, an anomalous rectification was induced by hyperpolarization-activated cation channel (Ih channel) in 11 out of 18 tested SON neurons. Bath of propofol reversibly decreased the anomalous rectification. Moreover, 0.1 mmol/L propofol elevated threshold level (P < 0.01) and decreased Max L. slope (P < 0.05) of the spike potential in SON neurons. Interestingly, 0.3 and 1.0 mmol/L propofol nullified APs in 6% (1/18) and 71% (12/17) tested SON neurons, respectively. In the SON neurons where APs were not nullified, propofol (0.3 mmol/L) decreased the amplitude of spike potential (P < 0.05). The higher concentrations of propofol (0.3 and 1.0 mmol/L) decreased firing frequencies evoked by depolarizing current pulses (0.1–0.7 nA), and shifted the current intensity-firing frequency relation curves downward and to the right. These results suggest that propofol decreases the excitability of SON neurons by inhibiting Ih and sodium channels.

Key words: supraoptic nucleus; propofol; hyperpolarization-activated cation channel; action potential; membrane potential; electrophysiology; rat

Received: 2011-10-15　　Accepted: 2012-02-06

Corresponding author: 汪萌芽　　E-mail: wangmy@wnmc.edu.cn

Citing This Article：

ZHANG Huan-Huan, WANG Meng-Ya. [Inhibitory effects of propofol on supraoptic nucleus neurons of rat hypothalamus in vitro.] [Article in Chinese]. Acta Physiol Sin 2012; 64 (2): 163-169 (in Chinese with English abstract).