Distribution of the mRNA for a metabotropic glutamate receptor (mGluR3) in the rat brain: An in situ hybridization study

Abstract

Distribution of the mRNA for a metabotropic glutamate receptor, mGluR3, which is coupled to the inhibitory cAMP cascade, was examined in the central nervous system of the adult albino rat by in situ hybridization. The hybridization signals of mGluR3 were detected not only on neuronal cells but also on many glial cells throughout the brain and spinal cord. In the neuronal cells, prominent expression of mGluR3 mRNA was seen in the thalamic reticular nucleus. Moderately labeled neurons were seen in the anterior olfactory nucleus, cerebral neo- and mesocortical regions, lateral amygdaloid nucleus, ventral part of the basolateral amygdaloid nucleus, dorsal endopiriform nucleus, supraoptic nucleus, superficial layers of the superior colliculus, inferior colliculus, interpeduncular nucleus, superior olivary nuclei, and Golgi cells in the cerebellar cortex. Weakly labeled neurons were observed in the striatum, nucleus accumbens, ventral pallidum, globus pallidus, entopeduncular nucleus, lateral hypothalamic area, hypothalamic paraventricular nucleus, medial habenular nucleus, anterior pretectal nucleus, Barrington's nucleus, Nucleus O, paragenual nucleus, trigeminal sensory complex, cochlear nuclei, dorsal motor nucleus of the trigeminal nerve, dorsal cap of the inferior olive, spinal dorsal horn, and lamina X of the spinal cord. The stellate cells in the cerebellar cortex, and neurons in the deep cerebellar nuclei were also labeled weakly. The granule cell layer of the dentate gyrus, as a whole, appeared to be labeled intensely, but each of the granule cells was labeled only weakly. No significant labeling was detected in the mitral and tufted cells in the olfactory bulb, hippocampal pyramidal cells, Purkinje and granule cells in the cerebellar cortex, or somatic motoneurons. The distribution of mGluR3 mRNA in particular neurons and glial cells indicates specific roles of mGluR3 in the glutamatergic system of the central nervous system.

NAAG Reduces NMDA Receptor Current in CA1 Hippocampal Pyramidal Neurons of Acute Slices and Dissociated Neurons

“…Moreover, in the presence of the selective and potent group 2 metabotropic receptor antagonist LY-341495, NAAG still reduced the NMDAR current following stimulation of the Schaffer collaterals. Indeed, group 2 metabotropic glutamate receptors are unlikely to be involved in the modulation of the CA3 to CA1 synapse examined in this study since mGluR3 receptor activation does not affect Schaffer collateral-evoked EPSCs recorded from CA1 pyramidal cells nor is there appreciable expression of mGluR3 RNA in either CA1 or CA3 pyramidal cells (Ohishi et al, 1993;Gereau and Conn, 1995). Our results with the paired-pulse stimulation are also consistent with a postsynaptic action of NAAG.…”

Group II metabotropic glutamate receptor activation attenuates peripheral sensitization in inflammatory states

“…Approximately 32% of unmyelinated and 28% of myelinated axons in rat digital nerves are positively labeled with antibodies directed against mGluR2/3. Since mRNA for mGluR3 has not been observed in DRG (Ohishi et al, 1993), it is highly likely that the effects reported here represent activation of mGluR2 exclusively. It is most likely that the inhibitory effect of APDC was due to activation of Group II mGluRs constitutively expressed on nociceptors.…”

Activation of Group II Metabotropic Glutamate Receptors in the Nucleus Accumbens Shell Attenuates Context-Induced Relapse to Heroin Seeking

“…mGluR 3 is expressed on both pre-and postsynaptic sites in the NAc and the caudate-putamen (Ohishi et al, 1993b;Tamaru et al, 2001). mGluR 2 in these brain areas is selectively expressed on presynaptic sites (Testa et al, 1998;Richards et al, 2005).…”