Coexistence of substance P- and methionine5-enkephalin-like immunoreactivity in nerve cells of the myenteric ganglia in the cat ileum.

Intramural ganglia of colchicine-injected cat ileum were examined immunohistochemically using antisera to substance P (SP), vasoactive intestinal polypeptide (VIP) and methionine5-enkephalin (ENK). SP- and ENK-like immunoreactive nerve cells were preferentially located in the myenteric ganglia, whereas VIP-like immunoreactive nerve cells were distributed in both myenteric and submucous ganglia. A small number of nerve cells in the myenteric ganglia showed immunoreactivities to both ENK and SP antisera, but not to VIP antiserum. These findings provide supportive evidence for the coexistence of SP and ENK in a small population of neurones in the cat myenteric plexus.