N. Fraeyman et al., Changes in the expression of alpha(2)-adrenergic receptor subtypes during maturation of neuronal cells from fetal pig superior cervical ganglia, DEV BRAIN R, 116(2), 1999, pp. 127-132
The expression of presynaptic alpha(2)-adrenereic receptor (alpha(2)-AR) su
btypes was investigated in cultured neurons from fetal pig superior cervica
l ganglion (SCG). Cells were incubated with chicken antibodies against alph
a(2)A-, alpha(2)B- or alpha(2)C-AR subtypes either alone or together with a
ntibodies against dopamine-beta-hydroxylase (D beta H, a marker for adrener
gic neurons) or against choline acetyl transferase (ChAT, a marker for chol
inergic neurons). We found immunoreactivity for ail three alpha(2)-AR subty
pes in SCG-cells when cultured for 8-11 days. The relative expression of th
e alpha(2)A-subtype was approximately 1/3 of that of alpha(2)B- and alpha(2
)C-AR. Co-localisation of all three alpha(2)-AR subtypes was observed in ce
lls expressing DPH or ChAT. Increasing the potassium concentration in the c
ulture medium increased the expression of DPH and decreased the expression
of the alpha(2)A- and alpha(2)C-subtype without altering the expression of
the alpha(2)B-subtype. Co-culture of neurons with pig splenocytes enhanced
the expression of ChAT and decreased the expression of the alpha(2)B-subtyp
e without altering the expression of alpha(2)A- and alpha(2)C-subtypes. Our
results indicate that the three alpha(2)-receptor subtypes are expressed o
n both noradrenergic and cholinergic nerves. Induction of the noradrenergic
phenotype favours the expression of the alpha(2)B-subtype over that of the
alpha(2)A- and alpha(2)C-subtype. Conversely, enhancement of the cholinerg
ic phenotype favours the expression of the alpha(2)A- and alpha(2)C-subtype
s over that of the alpha(2)B-subtype. Our results suggest that the alpha(2)
B-receptor is preferentially associated with noradrenergic nerve endings. (
C) 1999 Elsevier Science B.V. All rights reserved.