A Study about a Change in GABA(A) Receptors in the Trigeminal Mesencephalic Nucleus by Administration of an Agonist: —Investigation of Internalization of GABA(A) Receptors using Immunohistochemical Procedures—

Abstract

GABA(A) receptors are abundantly present in the trigeminal mesencephalic nucleus (Vmes) neurons involved in the senses of the masticatory muscle spindles and periodontal pressoreceptors. It has been reported that GABA (A) receptors may show internalization, which indicates the intracellular uptake of them after binding to an agonist. The internalization of GABA(A) receptors may be involved in the chewing motion-regulating mechanism. In this study, to investigate the internalization of GABA (A) receptors in Vmes, I analyzed the fluorescence intensity of neurons by fluorescence staining of Vmes neurons using immunohistochemical procedures. In Vmes neurons from rats treated with an agonist, the fluorescence intensity of a fluorescence-labeled secondary antibody was attenuated. Attenuation of fluorescence intensity indicating the presence of GABA (A) receptors suggested that administration of the agonist induced internalization of GABA (A) receptors. Furthermore, there was no attenuation of fluorescence intensity 6 hours after administration of the agonist, suggesting that attenuation of fluorescence intensity is not associated with drug administration-related irreversible cell injury.