Asynchrony in the Diurnal Rhythms of Dopaminergic D2 Receptors in Different Brain Regions of the Rat

Author: Torner C.   Aguilar-Roblero R.  

Publisher: Taylor & Francis Ltd

ISSN: 0929-1016

Source: Biological Rhythm Research, Vol.32, Iss.3, 2001-07, pp. : 363-388

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Abstract

Diurnal variations of dopaminergic D 2 receptors have been described in the striatum of rats, while other dopaminergic regions remain unstudied. Diurnal variations of dopamine D 2 receptors in the striatum, frontal cortex, and amygdala of the rat, were characterized by the stereospecific binding of [ 3 H]-spiperone. Clear rhythms were found in all these areas, but asynchronous to each other. Striatal receptors had diurnal variations with a single peak at 00:00 hours. Frontal cortex receptors showed two peaks at 00:00 and 12:00 hours. Amygdaline complex receptors had two peaks at 18:00 and 06:00 hours. Saturation binding curves and their Scatchard analysis indicated that the diurnal variations in [ 3 H]-spiperone binding are related to changes in receptor density rather than its affinity. The diurnal variations asynchrony in [ 3 H]-spiperone binding to dopaminergic D 2 receptors from different neural regions, suggest different regulation in each area. Other functional implications of these rhythms remains to be established.

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