Am. J. Respir. Cell Mol. Biol., Vol 15, No. 3, 09 1996, 374-381.
Expression of dopamine D2-receptor mRNA isoforms at the peripheral chemoreflex afferent pathway in developing rabbits
A Bairam, C Dauphin, F Rousseau and EW Khandjian
Unite de Recherche en Neonatologie, Hopital Saint Francois d'Assise, Universite Laval, Quebec City, Quebec, Canada.
The two isoforms of dopamine D2 receptor, D2 short (D2s) and D2 long, are
generated by alternative splicing of premessenger RNA and differ in the
length of their third cytoplasmic loop. Expression of these two isoforms
has not yet been studied at the level of the peripheral arterial
chemoreflex pathway. Using reverse transcriptase-polymerase chain reaction,
we evaluated the relative abundance of dopamine D2 receptor mRNA by
amplifying a common segment between both D2 receptor mRNA isoforms which
reflects the total D2-receptor mRNA and the two isoforms in the carotid
bodies, the petrosal ganglia, and the superior cervical ganglia of 1-, 10-,
and 25-day-old and adult rabbits, GH4C1 cell line, which does not express
D2 receptors, was used as negative control, whereas GH4C1 19 cell line,
which expresses only the D2s mRNA and the striatum of each age, were used
as positive controls. Both D2- receptor mRNA isoforms were found to be
expressed in all organs studied of newborn and adult rabbits. The
expression of total D2 receptor mRNA in 10- and 25-day-old and adult
rabbits was found to be 3-, 5-, and 1.5- fold more, respectively, compared
with 1-day-old rabbits for all organs studied. Our data suggest that the
expression of D2-receptor mRNA is modulated with age at the level of the
peripheral arterial chemoreflex pathway.
