Ultrastructural changes induced by 3-acetylpyridine in the central nervous system of adult rats.

Intraperitoneal administration of an antimetabolite of nicotinamide, 3-acetylpyridine (3-AP) to adult rats at the dose of 65 mg/kg selectively produces lesions of the olivary nerve cells in the medulla oblongata. The neurons show progressive swelling and destruction with cell retraction, apparently by interference of energy production by means of formation of nicotinamide adenin dinucleotide analogues. Although the selectiveness of injury of olivary nerve cells to the action of 3-AP still remains unclear, the findings in the present work along with those reported in the literature reflect the existence of a regional characteristic pattern of metabolism in the various structures of the central nervous system.