The polarity of neurochemically defined myenteric neurons in the human colon.
OBJECTIVE
Functional classes of enteric neurons in small mammals can be determined by neurochemical coding and axonal projections. The aim of this study was to describe the projections of vasoactive intestinal peptide (VIP)-, tachykinin (TK)-, and calretinin-immunoreactive (IR) interneurons and circular muscle motor neurons in human colon.


METHODS
Human colonic myenteric neurons were retrogradely filled with 1,1'-didodecyl 3,3,3',3'-indocarbocyanine perchlorate (DII) from either the myenteric plexus or the circular muscle layers in organotypic culture preparations. The preparations were then labeled with antisera, and the position and immunoreactivity of DII-filled neurons was recorded.


RESULTS
Nine percent of circular muscle motor neurons were labeled with TK immunoreactivity and these projected orally; 22% were VIP-IR and projected anally. Fifty-one percent of myenteric neurons that projected anally to the myenteric ganglia were VIP-IR and none were TK-IR. In contrast, 23% of neurons projecting orally were TK-IR but only 2% were VIP-IR. Calretinin immunoreactivity was present in 23% of neurons projecting anally and 3% projecting orally within the myenteric plexus. Six percent of circular muscle motor neurons had Dogiel type II morphology, and 50% of these were TK-IR.


CONCLUSIONS
Circular muscle motor neurons and myenteric interneurons with TK, VIP, and calretinin immunoreactivity in the human colon have distinct projections and polarity.
Wattchow
D A
DA
Department of Surgery, Flinders University, Adelaide, Australia.
Porter
A J
AJ
Brookes
S J
SJ
Costa
M
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001369:Axons / Q000737:chemistry / Q000648:ultrastructure; D064032:Calbindin 2; D003106:Colon / Q000294:innervation*; D046508:Culture Techniques; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007395:Interneurons / Q000737:chemistry / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000737:chemistry* / Q000166:cytology*; D009197:Myenteric Plexus / Q000166:cytology*; D009412:Nerve Fibers / Q000737:chemistry / Q000648:ultrastructure; D064030:S100 Calcium Binding Protein G / Q000032:analysis*; D015320:Tachykinins / Q000032:analysis*; D014660:Vasoactive Intestinal Peptide / Q000032:analysis*
C576764:CALB2 protein, human; D064032:Calbindin 2; D064030:S100 Calcium Binding Protein G; D015320:Tachykinins; D014660:Vasoactive Intestinal Peptide