NADPH-d positive neurons in the developing somatosensory cortex of the rat: effects of early and late environmental enrichment.
The effects of environmental enrichment upon the topographic arrangement of NADPH diaphorase-positive neurons (NADPH-d+ neurons) was studied in the somatosensory cortex of 56 Sprague-Dawley albino rats during early stages of development (18th, 24th, 30th and 60th postnatal days). This diaphorase is easily demonstrable, providing a convenient marker for quantitative studies. Environmental enrichment diminished the number of NADPH-d+ neurons and exerted its maximal influence during lactation, a time of exceptional cortical susceptibility. This implies that the magnitude of such effects on the density of NADPH-d+ neurons is age-dependent. Furthermore, it was found that the experience-dependent cortical changes persisted after a subsequent period without environmental stimulation. The effects of early environmental enrichment did not occur uniformly throughout the cerebral hemispheres but, instead, such effects were maximal in the latero-ventral sector of the cerebral cortex where a dramatic reduction in the number of NADPH-d+ neurons was observed. Particularly striking was the existence of a latero-medial sequence of NADPH-d+ neurons in the infragranular layer and a reversed distribution of labeled cells, in the supragranular layer. Both ontogenetic sequences of NADPH-d+ neurons remained unchanged during postnatal development in controls and enriched subjects (18th-60th postnatal days).
Fernández
V
V
Physiology and Biophysics Program, Biomedical Sciences Institute, School of Medicine, University of Chile, Santiago, Chile. nan@machi.med.uchile.cl
Bravo
H
H
Sanhueza
M
M
Inzunza
O
O
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D003712:Dendrites / Q000201:enzymology / Q000648:ultrastructure; D004777:Environment; D008297:Male; D008854:Microscopy, Electron; D009252:NADPH Dehydrogenase / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000166:cytology / Q000201:enzymology* / Q000254:growth & development*
D009252:NADPH Dehydrogenase