Abstract
Projections from the auditory cortex (AC) in the rat terminate in the dorsal cortex (DC) and in the external cortex (EC) of the inferior colliculus (IC), areas which exhibit a moderate number of nicotinamide-adenine dinucleotide phosphate-diaphorase (NADPH-d) positive neurons. NADPH-d co-localizes with nitric oxide synthase, which is responsible for the production of the transcellular messenger, nitric oxide.
Changes in NADPH-d staining in the IC were found after unilateral lesions of the AC. Lesions resulted in a reduction NADPH-d staining in neurons and neuropil within the ipsilateral DC and EC with the maximum reduction occurring 3-4 days after lesion.
The reduction in NADPH-d staining in the contralateral IC was less pronounced. Lesions affecting auditory areas Te 1 and Te 3 produced the largest decrease in NADPH-d staining in neurons and neuropil.
This finding may be related to the abolition of the influence of glutamatergic corticocollicular and commissural pathways.