Proceedings of The Physiological Society

Puerto de la Cruz, Tenerife (2003) J Physiol 548P, P174

Poster Communications

Activity-inactivity cycles in ring dove (Streptopelia roseogrisea): effect of tryptophan

J. Cubero, V. Valero, C. Barriga, R. Rial*, M. Rivero† and A.B. Rodríguez

Department of Physiology, Faculty of Science, University of Extremadura, 06071 Badajoz, Spain, *Animal Physiology Lab., Department FICS Biolgy, University of Illes Balears, 07071 Palma de Mallorca, Spain and †Laboratories Ordesa s.l. Barcelona, Spain

Melatonin is the most important hormone regulating the rhythm of sleep-wake cycles; it has the essential amino acid tryptophan as precursor (Dajk & Lockley 2002). The aim of this study was to determine the possible correlation of tryptophan adminstration with circadian activity-inactivity rhythms as well as with body temperature and weight.

The birds, ring dove (Streptopelia roseogrisea; n = 10 per experimental group) with diurnal habit, were maintained under a 12 h (08.00-20.00 h) light (3000 lux) and 12 h dark cycle and handled according to the quidelines of European Community Council Directives 86/6091 EEC. Tryptophan was administered orally at doses of 125 mg or 300 mg L-tryptophan (kg b.w.)-1 in single adminstration at 09.00 or 19.00 h. The anal temperature and the weignt of animals were measured at 10.00 h. The activity was recorded in pulses with one actometer per animal (two perpendicular infrared transmitters with a frequency of 4866 Hz). These activity pulses were logged every 5 min by a computer program (Das 16) throughout the experiment. The result are expressed as a comparison of the mean ± standard deviation (S.D.) activity between 10 animals admimistered tryptophan versus 10 control animals. Data were compared with Student's unpaired t test. Values of P

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