Abstract

MONOSODIUM GLUTAMATE ATTENUATES THE ACTION OF OXYTOCIN ON UTERINE SMOOTH MUSCLE BY AUGMENTING THE FUNCTION OF L-TYPE CALCIUM CHANNEL

Mukti Mondal*, Kaushik Sarkar* and Goutam Paul*

Abstract

Objective: We report here about the toxic effects of monosodium glutamate (MSG) on the function of uterine smooth muscle in rat. Key findings: We have observed significant potentiation of amplitude and inhibition of frequency of the contraction of uterus in chronic exposure groups and single dose acute exposure groups of rat. When MSG was applied in oxytocin pre-incubated uterine preparations, the amplitude of contraction was inhibited and frequency of the contraction was increased significantly in compared to oxytocin induced amplitude and frequency of the contraction of uterus. We have also observed no recovery of the nifedipine induced inhibition of the contraction of uterus after the application of MSG for the duration of the experiments, but significant recovery of the nifedipine induced contraction was observed when nifedipine was applied in MSG pre-incubated uterus. This result suggests that MSG potentiates the contraction of uterine smooth muscle probably augmenting the function of L-type calcium channel in the plasma membrane of uterine smooth muscle. Conclusion: In conclusion, MSG attenuates the action of oxytocin on the contraction of uterine smooth muscle probably by augmenting the L-type calcium channel in the plasma membrane of uterine smooth muscle.

Keywords: monosodium glutamate; oxytocin; nifedipine; L-type calcium channel; uterine smooth muscle.