IMMUNOHISTOCHEMICAL LOCALIZATION OF THE CLONED MU-OPIOID RECEPTOR IN THE RAT CNS

Citation
A. Mansour et al., IMMUNOHISTOCHEMICAL LOCALIZATION OF THE CLONED MU-OPIOID RECEPTOR IN THE RAT CNS, Journal of chemical neuroanatomy, 8(4), 1995, pp. 283-305
Citations number
75
Categorie Soggetti
Biology,Neurosciences
ISSN journal
08910618
Volume
8
Issue
4
Year of publication
1995
Pages
283 - 305
Database
ISI
SICI code
0891-0618(1995)8:4<283:ILOTCM>2.0.ZU;2-3
Abstract
Three opioid receptor types have recently been cloned that correspond to the pharmacologically defined mu, delta and K-1 receptors. In situ hybridization studies suggest that the opioid receptor mRNAs that enco de these receptors have distinct distributions in the central nervous system that correlate well with their known functions. In the present study polyclonal antibodies were generated to the C terminal 63 amino acids of the cloned mu receptor (335-398) to examine the distribution of the mu receptor-like protein with immunohistochemical techniques. m u receptor-like immunoreactivity is widely distributed in the rat cent ral nervous system with immunoreactive fibers and/or perikarya in such regions as the neocortex, the striatal patches and subcallosal streak , nucleus accumbens, lateral and medial septum, endopiriform nucleus, globus pallidus and ventral pallidum, amygdala, hippocampus, presubicu lum, thalamic and hypothalamic nuclei, superior and inferior colliculi , central grey, substantia nigra, ventral tegmental area, interpeduncu lar nucleus, medial terminal nucleus of the accessory optic tract, rap he nuclei, nucleus of the solitary tract, spinal trigeminal nucleus, d orsal motor nucleus of vagus, the spinal cord and dorsal root ganglia. In addition, two major neuronal pathways, the fasciculus retroflexus and the stria terminalis, exhibit densely stained axonal fibers. While this distribution is in excellent agreement with the known mu recepto r binding localization, a few regions, such as neocortex and cingulate cortex, basolateral amygdala, medial geniculate nucleus and the media l preoptic area fail to show a good correspondence. Several explanatio ns are provided to interpret these results, and the anatomical and fun ctional implications of these findings are discussed.