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Diurnal rhythm in the levels of the serotonin 5‐HT 1A receptors in the crayfish eyestalk
Author(s) -
CalderónRosete Gabina,
Flores Gonzalo,
RodríguezSosa Leonardo
Publication year - 2006
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.20252
Subject(s) - crayfish , eyestalk , serotonin , medicine , endocrinology , receptor , circadian rhythm , biology , 5 ht receptor , agonist , chemistry , neuroscience , ecology , hormone
The crayfish eyestalk (ES) has been postulated as a possible circadian clock. 5‐Hydroxytryptamine (5‐HT) has been shown to play the role of a neurotransmitter or a modulator in the ES. However, little is known about the 5‐HT receptors in the ES. The purpose of this work is to determine the specific binding sites using [ 3 H]8‐hydroxy‐2(di‐ n ‐propylamino)tetralin ([ 3 H]8‐OH‐DPAT), a specific agonist of the 5‐HT 1A receptor, and to characterize the diurnal rhythm in the binding by an autoradiography procedure in the crayfish ES. Data show the presence of a circadian rhythmicity in the level of the 5‐HT 1A receptors, principally in two regions: (a) the complex retina (R)–lamina ganglionaris (LG), with the acrophase at dusk and (b) the medulla terminalis (MT), where it was in antiphase. It is suggested that (1) the expression of levels of 5‐HT 1A receptors is modulated by light–dark (LD) cycles, (2) the level of 5‐HT 1A receptors in the R–LG and MT are in antiphase during the 24‐h cycle, and (3) there is a different mechanism of action of LD cycles in each of these two anatomical regions of the crayfish ES. Synapse 59:368–373, 2006. © 2006 Wiley‐Liss, Inc.