Enhanced visual responses in cat dLGN--potentiation by priming with excitatory amino acids.
Sustained iontophoresis of NMDA potentiated visual responses for minutes after the application in 16 of 38 cells (42%), peaking 3 min after the end of the application and declining to control levels within 12 min. Potentiation was also seen after application of ACPD (36%, n = 14) and AMPA (29%, n = 14), but not after application of ACh (n = 20). ACh also excites dLGN cells, but does not interact with amino acid receptors, and ACh receptors are not directly involved in the transmission of visual information. We suggest that this modulation is a form of visually induced potentiation which permits dynamic modification of the strength of visual information to be relayed to the cortex depending upon the history of previous activity levels.
Rivadulla
C
C
E.U. de Fisioterapia (Univesidade da Coruna) and Unidad de Cirugia Experimental (Hospital Juan Canalejo), Centro Universitario de Oza, Spain.
Grieve
K L
KL
Cudeiro
J
J
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002415:Cats; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D004357:Drug Synergism; D018846:Excitatory Amino Acids / Q000494:pharmacology*; D005829:Geniculate Bodies / Q000187:drug effects / Q000502:physiology*; D007478:Iontophoresis; D016202:N-Methylaspartate / Q000008:administration & dosage / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology; D010775:Photic Stimulation; D014796:Visual Perception / Q000187:drug effects / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D018846:Excitatory Amino Acids; D018696:Neuroprotective Agents; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D000109:Acetylcholine