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Updated: Nov 5, 2025
Use of Synaptic Zinc Histochemistry to Reveal Different Regions and Laminae in the Developing and Adult Brain
Published on: October 29, 2017
Membrane excitabilities in neonatal rat mesencephalic trigeminal neurons under dietary zinc deficiency
Saori Yamada1, Susumu Tanaka1, Soju Seki1
1First Department of Oral and Maxillofacial Surgery, Graduate School of Dentistry, Osaka University.
Purpose:
The present study aimed to evaluate the effects of zinc deprivation on the properties of membrane and spike-discharge features of mesencephalic trigeminal neurons (MTNs), which are important sensory neurons for oral-motor reflexes and rhythmical jaw movements.
Methods:
Neonatal Sprague Dawley rats (P10-12) were distributed equally into a normal diet group and a zinc-deficient diet (ZD) group. Whole cell patch-clamp recordings were obtained from MTNs from coronal brain slices.
Results:
Passive membrane properties showed a modest depolarized membrane potential and decreased cell capacitance in the ZD group. Zinc deprivation decreased the minimal current amplitude, which induced an action potential and increased the amplitude of afterhyperpolarization following the action potential. Negligible changes were observed for other action potential properties. A decreased burst duration was observed, accompanied by hastened spike frequency adaptation in the burst discharge. There was no difference in the resonant properties at both the subthreshold depolarized potential and hyperpolarized membrane potential between the control and ZD groups.
Conclusion:
These results suggests that neither the persistent sodium conductance nor slow inwardly rectifying conductance were altered; however, there appeared to be an increase in Ca2+-dependent K+ conductance in zincdeficient MTNs.
