Photic induction of Fos protein in the suprachiasmatic nucleus is inhibited by the NMDA receptor antagonist MK-801.
Exposure of rodents to light can induce expression of a number of immediate-early genes, including c-fos, in cells of the suprachiasmatic nucleus (SCN), a dominant pacemaker in the mammalian circadian system. We examined the effects of pre-treatment with the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801, on the induction of Fos-like immunoreactivity (Fos-lir) in cells in the hamster SCN. At doses of 3 and 5 mg/kg, MK-801 treatment blocked photic induction of Fos-lir in the rostral SCN and ventrolateral portions of the caudal SCN but failed to block induction of Fos-lir in a discrete region of the dorsolateral SCN. These results suggest that photic induction of Fos-lir in most of the SCN depends on activation of an NMDA-type receptor which is sensitive to MK-801, but that Fos-lir in one portion of the SCN is induced by a mechanism which is not antagonized by MK-801.
Abe
H
H
Department of Psychology, Dalhousie University, Halifax, N.S., Canada.
Rusak
B
B
Robertson
H A
HA
D000818:Animals; D006224:Cricetinae; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D007150:Immunohistochemistry; D008027:Light; D008297:Male; D008647:Mesocricetus; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*
D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate