Rearing with monocular lid suture induces abnormal NADPH‐diaphorase staining in the lateral geniculate nucleus of cats

Abstract

We investigated the changes in NADPH-diaphorase staining that occur in the lateral geniculate nucleus of cats following rearing with monocular lid suture. This staining allows visualization of the synthesizing enzyme of nitric oxide, a neuromodulator associated with plasticity. In the lateral geniculate nucleus of normally reared cats, NADPH-diaphorase exclusively labels the axons and terminals of an input from the parabrachial region of the brainstem; no geniculate cells in the A-laminae are labeled. Early monocular lid suture has no obvious effect on the NADPH-diaphorase staining of parabrachial axons. However, this lid suture results in the abnormal appearance of NADPH-diaphorase staining for geniculate somata. These cells are located primarily in the nondeprived laminae. Double-labeling experiments indicate that these cells with abnormal NADPH-diaphorase reactivity are Y relay cells: NADPH-diaphorase staining is found in cells retrogradely labeled from visual cortex; it is found in cells labeled with a monoclonal antibody for CAT-301, which selectively targets Y cells; it is not found in cells labeled with an anti-GABA antibody, which targets interneurons. Also, NADPH-diaphorase labeled cells are among the largest cells in the nondeprived laminae, again suggesting that they are Y relay cells. We cannot suggest a specific mechanism for this induction of NADPH-diaphorase labeling, but it does not seem to be due to abnormal binocular competition induced by the monocular lid suture.

Sight and insight – on the physiological role of nitric oxide in the visual system

“…Further indirect results on the putative role of NO on development and plasticity have also been obtained in cats. After monocular lid suturing as kittens, adult cats showed an abnormal presence of NADPH-d-positive cells within the dLGN, which was not seen in normally reared controls, clearly indicating that NOS activity can be induced (or perhaps retained) by visual deprivation 71 .…”

Ontogeny of NADPH-diaphorase in rat forebrain and midbrain

“…The possibility also exists that even though NADPH-d activity appears mature at P10-P20, activitydependent morphological and physiological changes continue throughout adulthood in the NO/cGMP system. Eye enucleation or monocular lid suture soon after birth results in changes in morphology or number of NADPH-dpositive neurons of the superficial layers of the SC or lateral geniculate nucleus (Günlük et al 1994;Vercelli and Cracco 1994). These changes that occur after a major source of input has been deprived prior to the appearance of NADPH-d expression, demonstrate that NADPH-d expression in these nuclei is regulated trans-synaptically by visual inputs.…”

Two types of interneurons in the cat visual thalamus are distinguished by morphology, synaptic connections, and nitric oxide synthase content

“…However, the variability in staining may be due to other unidentified variables. Because the distribution of BNOS in the LGN changes during development (Guido et al, 1997;Carden et al, 1998) and during experimental manipulation (Gü nlü k et al, 1994), it is possible that, under certain conditions, there may be more cellular expression of BNOS in the A laminae. In any case, it appears that, in the normal LGN, the levels of cellular BNOS are lower than in other thalamic nuclei.…”