Abstract

 Introduction

 Pineal NAT and SCN photoinduction rhythm

 Spontaneous c-Fos induction

 Discussion and conclusions

 References
 
 
 

Discussion
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 The rat suprachiasmatic nucleus (SCN) controls the circadian rhythm in the pineal N - acetyltransferase (NAT) activity which drives the rhythmic melatonin production. A question arises whether the melatonin production is controlled mostly by the SCN or whether its regulation is partly independent of the SCN. To elucidate the question, the pineal NAT rhytms, after photic and nonphotic stimuli and during postnatal development, was compared with the SCN intrinsic rhythmicity followed on the rhythm of c-fos gene photoinduction in the ventrolateral SCN and on the rhythm of the spontaneous c-Fos immunoreactivity in the dorsomedial SCN. The comparisons showed that changes in the pineal rhythmicity just reflected changes of the SCN rhythmicity, and suggested a complex nature of the underlying SCN pacemaker. 

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Presentation Number SAillnerova0650
Keywords: circadian, SCN, pineal, melatonin, photoperiod