Expression of sodium channel Nav1.6 in cholinergic myenteric neurons of guinea pig proximal colon.
We wished to establish the functional identity of Na(v)1.6-expressing myenteric neurons of the guinea pig proximal colon by determining the extent of colocalization of Na(v)1.6 and selected neurochemical markers. Na(v)1.6-like immunoreactivity (-li) was primarily localized to the hillock and initial segments of myenteric neurons located near junctions with internodal fiber tracts. Immunoreactivity for Na(v)1.6 was co-localized with choline-acetyltransferase-li, representing 96% of Na(v)1.6-immunoreactive neurons; about 5% of these neurons showed co-localization with calretinin-li, but none with substance-P-li. Cholinergic neurons expressing Na(v)1.6 were amongst the smallest (somal area <300 mum(2)) of all cholinergic myenteric neurons observed. Only three of 234 Na(v)1.6-immunoreactive neurons exhibited nNOS-li, and none co-localized with calbindin-li. These data suggest that Na(v)1.6 is expressed in a small uniform population of cholinergic myenteric neurons that lie within the guinea pig proximal colon and that are likely to function as excitatory motor neurons.
Bartoo
A C
AC
Program in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, WA 99164-6520, USA.
Sprunger
L K
LK
Schneider
D A
DA
D000818:Animals; D002799:Cholinergic Fibers / Q000378:metabolism*; D003106:Colon / Q000166:cytology / Q000378:metabolism*; D006168:Guinea Pigs; D007150:Immunohistochemistry; D008297:Male; D009197:Myenteric Plexus / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D015222:Sodium Channels / Q000096:biosynthesis*
D015222:Sodium Channels