The effect of sevoflurane on the cognitive function of rats and its association with the inhibition of synaptic transmission.

To observe the effects of different concentrations of sevoflurane on synaptotagmin 1 (Syt1) expression, synaptic long term depression (LTD), and paired pulse depression (PPD) in the rat hippocampus as well as to investigate the association between these effects and the cognitive function of rats. A total of 24 male Sprague-Dawley (SD) rats were selected and randomly divided into 3 groups: the control group (group A), which inhaled air; group B, which inhaled 0.65 minimum alveolar concentration (MAC) sevoflurane for 2 h; and group C, which inhaled 1.30 MAC sevoflurane for 2 h. The subsequent experiments were performed after one day. (1) Y maze tests were performed, and the expression of Syt1 in hippocampal tissues was detected using western blot. (2) The changes in LTD and PPD in rat hippocampal slices were examined using electrophysiological techniques. Compared to the control group, the cognitive function was decreased and Syt1 expression in the hippocampus was significantly decreased in rats in the 1.30 MAC sevoflurane inhalation group. After 60 min of low frequency stimulation, the amplitudes of population spike (PS) potentials in rat hippocampal slices were significantly decreased. After induction of PPD, the P2/P1 ratio was significantly increased. No indicators in the 0.65 MAC sevoflurane inhalation group showed any significant changes. Inhalation of high concentrations of sevoflurane significantly reduced Syt1 protein levels in the rat hippocampus, significantly inhibited the release of presynaptic neurotransmitters, and reduced the efficiency of synaptic transmission, thus causing memory impairment.