Calbindin, tyrosine hydroxylase and opioid-like immunoreactivity in the intestinal nerve of Remak of the domestic fowl.

Four classes of neurons were identified in both juxta-jejunal and juxta-rectal ganglia of Remak's nerve of the domestic fowl using double-labeling immunohistochemistry. Neurons immunoreactive (IR) for tyrosine hydroxylase (TH) formed a mutually exclusive subpopulation from neurons displaying calbindin (CaBP)-IR. Between 48-72% of juxta-jejunal neurons labeled for TH whereas 36-57% of juxta-rectal neurons displayed TH-IR. CaBP-IR was present in 18-40% of juxta-jejunal neurons; this increased to 31-46% in juxta-rectal neurons. The majority of CaBP-IR neurons (78-85%) also displayed opioid (beta-EP)-IR. Within each ganglion a small percentage of neurons (4-18%) were non-IR with any of the three antibodies. This is the first report of an immunohistochemically identified subpopulation of non-catecholaminergic neurons within the juxta-jejunal ganglia of Remak's nerve. It is proposed that these perikarya are a major source of the CaBP-IR and opioid-IR nerve fibers found in the chicken gut.