Origin and distribution of cholecystokinin-containing nerve terminals in the lumbar dorsal horn and nucleus caudalis of the cat.

Immunohistochemical bridge methods were used to localize cholecystokinin (CCK)-like immunoreactivity in the lumbar dorsal horn (DH) and nucleus caudalis (NC) of the cat. The CCK-positive structures were either dot- or fiber-like. The distribution of CCK-like immunoreactivity in the DH and NC was narrower than substance P (SP)-like immunoreactivity in adjacent sections. CCK- and SP-like immunoreactivity in the DH and NC was severely depleted 7--10 days following rhizotomy of either the dorsal roots or the 5th, 9th and 10th cranial nerves, respectively; enkephalin-like immunoreactivity in adjacent sections was unaffected. Cervical hemisection had no effect on either CCK- or SP-like immunoreactivity in the DH.