TY - JOUR
T1 - Norepinephrine transporter expression in cholinergic sympathetic neurons
T2 - Differential regulation of membrane and vesicular transporters
AU - Habecker, Beth A.
AU - Klein, Michael G.
AU - Cox, Brian C.
AU - Packard, Benjamin A.
N1 - Funding Information:
VMAT2 immunohistochemical studies were carried out in the Neural Development Section, National Institute of Neurological Disorders and Stroke, NIH. This work was sponsored by MRF Oregon No. 9724 and American Heart Association Grant-in-Aid 9750083N (B.A.H.), an NIH summer undergraduate fellowship to B.A.P., and a Murdock Charitable Trust/OHSU Heart Research Center undergraduate fellowship to B.C.C. The authors thank Dr. Richard Simerly for TH, NET, and cyclophilin plasmids; Regeneron Pharmaceuticals, Inc., for Axokine (a modified form of recombinant CNTF); Drs. Susan Amara and Randy Blakely for anti-NET antisera; Dr. Story Landis for anti-VIP antiserum and for critically reading the manuscript; and Drs. Steve Asmus and Christine Brennan for critically reading the manuscript.
PY - 2000/4/1
Y1 - 2000/4/1
N2 - Sympathetic neurons that undergo a noradrenergic to cholinergic change in phenotype provide a useful model system to examine the developmental regulation of proteins required to synthesize, store, or remove a particular neurotransmitter. This type of change occurs in the sympathetic sweat gland innervation during development and can be induced in cultured sympathetic neurons by extracts of sweat gland-containing footpads or by leukemia inhibitory factor. Sympathetic neurons initially produce norepinephrine (NE) and contain the vesicular monoamine transporter 2 (VMAT2), which packages NE into vesicles, and the norepinephrine transporter (NET), which removes NE from the synaptic cleft to terminate signaling. We have used a variety of biochemical and molecular techniques to test whether VMAT2 and NET levels decrease in sympathetic neurons which stop producing NE and make acetylcholine. In cultured sympathetic neurons, NET protein and mRNA decreased during the switch to a cholinergic phenotype but VMAT2 mRNA and protein did not decline. NET immunoreactivity disappeared from the developing sweat gland innervation in vivo as it acquired cholinergic properties. Surprisingly, NET simultaneously appeared in sweat gland myoepithelial cells. The presence of NET in myoepithelial cells did not require sympathetic innervation. VMAT2 levels did not decrease as the sweat gland innervation became cholinergic, indicating that NE synthesis and vesicular packaging are not coupled in this system. Thus, production of NE and the transporters required for noradrenergic transmission are not coordinately regulated during cholinergic development. (C) 2000 Academic Press.
AB - Sympathetic neurons that undergo a noradrenergic to cholinergic change in phenotype provide a useful model system to examine the developmental regulation of proteins required to synthesize, store, or remove a particular neurotransmitter. This type of change occurs in the sympathetic sweat gland innervation during development and can be induced in cultured sympathetic neurons by extracts of sweat gland-containing footpads or by leukemia inhibitory factor. Sympathetic neurons initially produce norepinephrine (NE) and contain the vesicular monoamine transporter 2 (VMAT2), which packages NE into vesicles, and the norepinephrine transporter (NET), which removes NE from the synaptic cleft to terminate signaling. We have used a variety of biochemical and molecular techniques to test whether VMAT2 and NET levels decrease in sympathetic neurons which stop producing NE and make acetylcholine. In cultured sympathetic neurons, NET protein and mRNA decreased during the switch to a cholinergic phenotype but VMAT2 mRNA and protein did not decline. NET immunoreactivity disappeared from the developing sweat gland innervation in vivo as it acquired cholinergic properties. Surprisingly, NET simultaneously appeared in sweat gland myoepithelial cells. The presence of NET in myoepithelial cells did not require sympathetic innervation. VMAT2 levels did not decrease as the sweat gland innervation became cholinergic, indicating that NE synthesis and vesicular packaging are not coupled in this system. Thus, production of NE and the transporters required for noradrenergic transmission are not coordinately regulated during cholinergic development. (C) 2000 Academic Press.
KW - Cholinergic differentiation
KW - Norepinephrine transporter (NET)
KW - Sympathetic development
KW - Vesicular monoamine transporter (VMAT2)
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U2 - 10.1006/dbio.2000.9631
DO - 10.1006/dbio.2000.9631
M3 - Article
C2 - 10720433
AN - SCOPUS:0034176093
SN - 0012-1606
VL - 220
SP - 85
EP - 96
JO - Developmental Biology
JF - Developmental Biology
IS - 1
ER -