Unscheduled DNA synthesis in rat adult myenteric neurons: an immunohistochemical study

Unscheduled DNA synthesis refers to DNA synthesis not followed by cell divi sion. Previous studies have suggested that this phenomenon may occur in neu rons from peripheral myenteric ganglia in conditions of functional hypersti mulation. In order to verify these observations, we have carried on an immu nohistochemical study on myenteric neurons from the hypertrophic intestinal loops upstream from a partial obstruction tan experimental condition that induces a relevant increase of the neuronal workload) after labelling with two different markers: the proliferating cell nuclear antigen (PCNA), that is specifically expressed in cell nuclei during the S-phase, and the protei n gene product 9.5 (PGP 9.5), a specific marker of nerve cells. While no my enteric neuron immunopositive for the anti-PCNA antibody was found in the c ontrol intestine, in the hypertrophic myenteric ganglia some neurons were p ositive for PCNA. These results provide an unequivocal evidence on the exis tence of unscheduled DNA synthesis in myenteric neurons from the hypertroph ic intestine. NeuroReport 12:2165-2168 (C) 2001 Lippincott Williams & Wilki ns.