title: Modification of neurotransmitter receptor sensitivity in cat visual cortex during the critical period.
abstract: We have examined the characteristics of various receptors in cat visual cortex during postnatal development. These included beta-adrenergic, GABA, benzodiazepine and acetylcholine receptors. For each population of receptor the number (Bmax) and affinity (Kd) were examined as a function of postnatal age (3 days-adult). For all receptors examined, the Bmax increased during development from low early values to a peak within the critical period. The Kd also changed during development for most receptors. The simultaneous alterations in Bmax and Kd necessitate defining a term which takes both of these receptor properties into consideration. This term, called receptor sensitivity (RS), provides a more comprehensive measure of receptor function than either Bmax or Kd alone. Using this measure, we find that receptor sensitivity is low near birth for the 4 receptor populations studied, rises to a peak within the first two months of life, and then declines to near-neonatal levels for 3 of the 4 receptor populations.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002415:Cats; D008297:Male; D011869:Radioligand Assay; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D011950:Receptors, Cholinergic / Q000502:physiology; D011963:Receptors, GABA-A / Q000502:physiology; D017981:Receptors, Neurotransmitter / Q000032:analysis / Q000502:physiology*; D014793:Visual Cortex / Q000032:analysis / Q000254:growth & development*
chemical_list: D011943:Receptors, Adrenergic, beta; D011950:Receptors, Cholinergic; D011963:Receptors, GABA-A; D017981:Receptors, Neurotransmitter