title: Changes in the expression of alpha(2)-adrenergic receptor subtypes during maturation of neuronal cells from fetal pig superior cervical ganglia.
abstract: The expression of presynaptic alpha(2)-adrenergic receptor (alpha(2)-AR) subtypes was investigated in cultured neurons from fetal pig superior cervical ganglion (SCG). Cells were incubated with chicken antibodies against alpha(2)A-, alpha(2)B- or alpha(2)C-AR subtypes either alone or together with antibodies against dopamine-beta-hydroxylase (DbetaH, a marker for adrenergic neurons) or against choline acetyl transferase (ChAT, a marker for cholinergic neurons). We found immunoreactivity for all three alpha(2)-AR subtypes in SCG-cells when cultured for 8-11 days. The relative expression of the 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 cells expressing DbetaH or ChAT. Increasing the potassium concentration in the culture medium increased the expression of DbetaH 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-subtype 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 on 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 cholinergic phenotype favours the expression of the alpha(2)A- and alpha(2)C-subtypes over that of the alpha(2)B-subtype. Our results suggest that the alpha(2)B-receptor is preferentially associated with noradrenergic nerve endings.
authors.affiliation: Heymans Institute of Pharmacology, University of Gent Medical School, De Pintelaan 185, B-9000, Gent, Belgium. norbert.fraeyman@rug.ac.be
authors.forename: N
authors.initials: N
authors.lastname: Fraeyman
authors.forename: P
authors.initials: P
authors.lastname: Vanscheeuwijck
authors.forename: J M
authors.initials: JM
authors.lastname: Wang
authors.forename: Y
authors.initials: Y
authors.lastname: Huang
authors.forename: W P
authors.initials: WP
authors.lastname: De Potter
authors.forename: J W
authors.initials: JW
authors.lastname: Regan
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000502:physiology; D005314:Embryonic and Fetal Development / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D018341:Receptors, Adrenergic, alpha-2 / Q000378:metabolism*; D017783:Superior Cervical Ganglion / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D013552:Swine
chemical_list: D018341:Receptors, Adrenergic, alpha-2