Glutamatergic antagonists do not attenuate light-induced fos protein in rat intergeniculate leaflet.
Photic information that entrains circadian rhythms is transmitted to the suprachiasmatic nucleus (SCN) from the retina and from the retinorecipient intergeniculate leaflet (IGL). Expression of light-induced Fos protein in SCN neurons is correlated with the effectiveness of such light to induce phase shifts, and is prevented by pretreatment with glutamate receptor antagonists that prevent phase shifts as well. In the present study we demonstrate that treatments with N-methyl-d-aspartate (NMDA) and non-NMDA receptor antagonists prior to light pulses during the subjective night have no effect on light-induced Fos immunoreactivity (Fos-IR) in IGL neurons despite attenuating Fos-IR in the SCN. Transmission of photic information along retinogeniculate and retinohypothalamic pathways appears to be mediated by different mechanisms.
Edelstein
K
K
Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, 1455 de Maisonneuve Blvd., West H-1013, Montreal, Quebec, Canada.
Amir
S
S
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology / Q000528:radiation effects; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005829:Geniculate Bodies / Q000033:anatomy & histology / Q000187:drug effects* / Q000528:radiation effects*; D008027:Light; D008297:Male; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000502:physiology
D018691:Excitatory Amino Acid Antagonists; D016760:Proto-Oncogene Proteins c-fos; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate