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Distribution of α 1A adrenergic receptor m RNA in the rat brain visualized by in situ hybridization
Author(s) -
Domyancic Anna V.,
Morilak David A.
Publication year - 1997
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/(sici)1096-9861(19970929)386:3<358::aid-cne3>3.0.co;2-0
Subject(s) - biology , riboprobe , in situ hybridization , zona incerta , neocortex , olfactory bulb , neuroscience , piriform cortex , raphe nuclei , anatomy , nucleus , receptor , amygdala , central nervous system , gene expression , serotonergic , serotonin , biochemistry , gene
Norepinephrine has been implicated in a number of physiological, behavioral, and cellular modulatory processes in the brain, and many of these modulatory effects are attributable to α 1 adrenergic receptors. At least three α 1 receptor subtypes have been identified by molecular criteria, designated α 1A , α 1B , and α 1D . The distributions of α 1B and α 1D receptor mRNA expression in rat brain have been described previously, but the cDNA for the rat α 1A receptor has only recently been cloned and characterized. In the present study, we used a radiolabelled riboprobe derived from the rat α 1A receptor cDNA to describe the distribution of α 1A message expression in the rat brain. The highest levels of α 1A adrenergic receptor mRNA expression were seen in the olfactory bulb, tenia tectae, horizontal diagonal band/magnocellular preoptic area, zona incerta, ventromedial hypothalamus, lateral mammillary nuclei, ventral dentate gyrus, piriform cortex, medial and cortical amygdala, magnocellular red nuclei, pontine nuclei, superior and lateral vestibular nuclei, brainstem reticular nuclei, and several cranial nerve motor nuclei. Dual in situ hybridization combining a radioactive riboprobe for choline acetyltransferase mRNA with a digoxigenin‐labeled α 1A riboprobe in the fifth and seventh cranial nerve motor nuclei showed that the α 1A mRNA is expressed in cholinergic motor neurons. Prominent α 1A hybridization signal was also seen in the neocortex, claustrum, lateral amygdala, ventral cochlear nucleus, raphe magnus, and in the ventral horn of thoracic spinal cord. This overall pattern of expression, considered in comparison with that previously described for the other α 1 adrenergic receptor subtypes, may shed light on the different roles of the α 1 receptors in mediating the neuromodulatory effects of norepinephrine in processes such as arousal, neuroendocrine control, sensorimotor regulation, and the stress response. J. Comp. Neurol. 386:358‐378, 1997. © 1997 Wiley‐Liss, Inc.