Journal of Zhejiang University SCIENCE
(ISSN 1009-3095, Monthly)
2002   Vol. 3   No. 5   p.591-593

The effect of Jujuboside A on the evoked field potentials of granule cells in dentate gyrus

FENG Zhou-yan(封洲燕)(College of Life Sciences, Zhejiang University, Hangzhou 310027,China)  
ZHENG Xiao-xiang(郑筱祥)(College of Biomedical Engineering and Instrument Science, Zhejiang University,Hangzhou 310027,China)  

Abstract:Jujuboside A (JuA) is a main component of Jujubogenin extracted from the seeds of Ziziphus. The authors have not seen any report on JuA's direct effect on the neurons of the central nervous system. This study aimed to assess the effect of JuA on paired-pulse responses of dentate gyrus granule cells in urethane-anaesthetized rats, used intracerebroventricular (i.c.v.) JuA to mimic in vitro bath conditions in vivo. Paired-pulse stimuli with 80ms interpulse interval were used to stimulate the perforant pathway. Evoked responses were recorded in the dentate gyrus cell layer after i.c.v. administration of 0.9% normal saline or JuA. In the first responses, the slopes of excitatory postsynaptic potential (EPSP1) and the amplitudes of population spike (PS1) decreased significantly after administration of JuA while the PS1 latencies increased significantly. In the second responses, the EPSP2 slopes and PS2 latencies were changed similarly to those of the first ones, but PS2 amplitudes increased. The results showed that JuA may have some inhibitory effect on the granule cell excitability mediated by presynaptic mechanism but may have little effect on the excitability mediated by postsynaptic mechanism since the second evoked N-methyl-D-aspartic mediating paired-pulse facilitation is a postsynaptic mechanism.
Keywords:Field potential, Dentate gyrus, Jujuboside A(JuA), Inhibitory effect

CLC Number:R965  Document ID:A

Foundation Item:Project supported by the National Key Scientific and Technological Planning Fund of China (Grant 99-929-04-03), and by the Visiting Scholar Fund of Key Laboratory from the Education Ministry of China
Author Resume:ZHENG Xiao-xiang(郑筱祥),E-mail: zxx@mail.hz.zj.cn

References:

[1]Albertson, T.E., Joy, R.M., 1989. Modification of evoked hippocampal dentate inhibition by diazepam and three antagonists in urethane-anesthetized rats. Experimental Neurology, 106(2):142-149.
[2]Andersen,P., Bliss,T.V.P., Skrede,K.K., 1971. Lamellar organization of hippocampal excitatory pathways. Experimental Brain Research, 13(2):222-238.
[3]Gilbert,M.E., Mack,C.M., 1999. Field potential recordings in dentate gyrus of anesthetized rats: stability of baseline. Hippocampus, 9(3):277-287.
[4]John,T.h.R., Norton, W. M.Biotechnology, 1999. Instability of dentate gyrus field potentials in awake and anesthetized rats. Hippocampus, 9(3):333-339.
[5]Joy, R.M., Albertson, T.E., 1993. NMDA receptors have a dominant role in population spike-paired pulse facilitation in the dentate gyrus of urethane-anesthetized rats. Brain Research, 604(1-2):273-282.
[6]Paul, C. C., Carolyn, W. H., 1998. Intracerebroventricular norepinephrine potentiation of the perforant path-evoked potential in dentate gyrus of anesthetized and awake rats: a role for both (- and (-adrenoceptor activation. Brain Research, 787(1):59-70.
[7]Wu, S.X., Zhang, J.X., Xu, T., et al., 1993. Effects of seeds, leaves and fruits of Ziziphus spinosa and jujuboside A on central nervous system function. Chung Kuo Chung Yao Tsa Chih, 18(11):685-687(in Chinese).
[8]Ying, J., Guo, L.G. 1993. The Study of Modern Chinese Medicines and Their Clinical Applications, Xue Yuan publishing company, Beijing, p. 671-674.
[9]Zhou, Y., Li, Y., Wang, Z., et al., 1994. 1H NMR and spin-labeled EPR studies on the interaction of calmodulin with Jujuboside A. Biochemical and Biophysical Research Communications, 202(1):148-154(in Chinese).


Manuscript Received:2001 July 2

Manuscript Revised:2001 Nov. 3

Published:2002 Dec. 1