P. Subramony et Se. Dryer, NEUREGULINS STIMULATE THE FUNCTIONAL EXPRESSION OF CA2-ACTIVATED K+ CHANNELS IN DEVELOPING CHICKEN PARASYMPATHETIC NEURONS(), Proceedings of the National Academy of Sciences of the United Statesof America, 94(11), 1997, pp. 5934-5938
The developmental expression of macroscopic Ca2+-activated K+ currents
(I-K[Ca]) in chicken ciliary ganglion (CG) neurons is dependent in pa
rt on trophic factors released from preganglionic nerve terminals. Neu
regulins are expressed in the preganglionic neurons that innervate the
chicken CG and are therefore plausible candidates for this activity.
Application of 1 nM beta 1-neuregulin peptide for 12 hr evokes a large
(7- to 10-fold) increase in I-K[Ca] in embryonic day 9 CG neurons, ev
en in the presence of a translational inhibitor. A similar posttransla
tional effect is produced by high concentrations (10 nM) of epidermal
growth factor and type alpha transforming growth factor but not by 10
nM alpha 2-neuregulin peptide or by neurotrophins at 40 ng.ml(-1). bet
a 1-neuregulin treatment for 12 hr also confers Ca2+ sensitivity onto
large-conductance (285 pS) K+ channels observed in inside-out patches.
beta-Neuregulins have no effect on voltage-activated Ca2+ currents of
CG neurons. These data support the hypothesis that beta-neuregulins m
ediate the trophic effects of preganglionic nerve terminals on the ele
ctrophysiological differentiation of developing CG neurons.