TY - JOUR
T1 - Neuronal nicotinic receptor expression in sensory neurons of the rat trigeminal ganglion
T2 - Demonstration of α3β4, a novel subtype in the mammalian nervous system
AU - Flores, Christopher M.
AU - DeCamp, Raquel M.
AU - Kilo, Sonja
AU - Rogers, Scott W.
AU - Hargreaves, Kenneth M.
PY - 1996/12/15
Y1 - 1996/12/15
N2 - The identification of a family of neuronal nicotinic receptor subunit genes establishes the potential for multiple subtypes with diverse physiological functions. Virtually all of the high affinity nicotinic receptors measured to date in the rodent CNS are composed of α4 and β2 subunits only. However, the demonstration of other subunit transcripts in a variety of central and peripheral nervous tissues suggests a greater degree of receptor subtype heterogeneity than so far has been elucidated. The purpose of the present studies was to determine at the mRNA and protein levels which neuronal nicotinic receptor subunits are expressed by sensory neurons of the rat trigeminal ganglion and in what combinations these gene products associate to form neuronal nicotinic receptor subtypes in this tissue. Radioreceptor binding analysis indicated that in the adult rat trigeminal ganglion there exist at least two nicotinic receptor binding sites with differing affinities for [3H]-epibatidine. In situ hybridization histochemical studies revealed the existence of mRNA encoding the α3, α4, α5, β2, and β4 subunits, but not the α2 subunit. Immunoprecipitation with subunit-specific antisera demonstrated that each of the subunits present in the ganglion at the mRNA level is a constituent of nicotinic receptors capable of binding 3H-epibatidine. Various applications of these approaches yielded strong evidence that, in addition to α4β2, which is thought to be the predominant neuronal nicotinic receptor subtype in the rodent CNS, trigeminal sensory neurons express as the principal subtype α3β4, which has not been demonstrated previously in mammalian nervous tissue.
AB - The identification of a family of neuronal nicotinic receptor subunit genes establishes the potential for multiple subtypes with diverse physiological functions. Virtually all of the high affinity nicotinic receptors measured to date in the rodent CNS are composed of α4 and β2 subunits only. However, the demonstration of other subunit transcripts in a variety of central and peripheral nervous tissues suggests a greater degree of receptor subtype heterogeneity than so far has been elucidated. The purpose of the present studies was to determine at the mRNA and protein levels which neuronal nicotinic receptor subunits are expressed by sensory neurons of the rat trigeminal ganglion and in what combinations these gene products associate to form neuronal nicotinic receptor subtypes in this tissue. Radioreceptor binding analysis indicated that in the adult rat trigeminal ganglion there exist at least two nicotinic receptor binding sites with differing affinities for [3H]-epibatidine. In situ hybridization histochemical studies revealed the existence of mRNA encoding the α3, α4, α5, β2, and β4 subunits, but not the α2 subunit. Immunoprecipitation with subunit-specific antisera demonstrated that each of the subunits present in the ganglion at the mRNA level is a constituent of nicotinic receptors capable of binding 3H-epibatidine. Various applications of these approaches yielded strong evidence that, in addition to α4β2, which is thought to be the predominant neuronal nicotinic receptor subtype in the rodent CNS, trigeminal sensory neurons express as the principal subtype α3β4, which has not been demonstrated previously in mammalian nervous tissue.
KW - [H]-epibatidine
KW - immunoprecipitation
KW - in situ hybridization
KW - mRNA
KW - nicotinic receptor subtype
KW - radioreceptor binding
KW - sensory neurons
KW - subunit composition
KW - trigeminal ganglion
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U2 - 10.1523/jneurosci.16-24-07892.1996
DO - 10.1523/jneurosci.16-24-07892.1996
M3 - Article
C2 - 8987817
AN - SCOPUS:0029826712
SN - 0270-6474
VL - 16
SP - 7892
EP - 7901
JO - Journal of Neuroscience
JF - Journal of Neuroscience
IS - 24
ER -