摘要:

Some fish have a good vision in red light, although this spectral bandwidth is rapidly absorbed by water. The question thus arises as to whether those wavelengths could entrain the circadian activity rhythm in juvenile brown trouts (Salmo truttaL.).

ISSN:0022-1945    

DOI:10.1080/09291019009360029

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291019009360036

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Inbred mouse strains differ in the expression of free‐running circadian activity rhythms. Although previous studies have suggested that BALB/c mice fail to display coherent rhythmicity under constant light, these studies presented only averaged data, and not individual animals’ activity patterns. In the present study, wheel‐running activity rhythms were monitored from individual BALB/c mice during long‐term exposure to constant red light All mice displayed dramatic lability of circadian activity rhythms, characterized by spontaneous alterations in both free‐running period and rhythm coherence. These results suggest that the circadian system in this strain is composed of a population of weakly‐coupled circadian oscillators.

ISSN:0022-1945    

DOI:10.1080/09291019009360030

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Visual sensitivity of the horseshoe crab,Limulus polyphemus,was followed over the course of a year using both physiological and behavioral criteria. An electroretinographic (ERG) index was derived from ventral eye intensity‐latency functions. A behavioral signal detectability (BSD) index was derived from the relative frequency of reflex tail flicks occurring when the ventral eye was in the dark or in the light.

ISSN:0022-1945    

DOI:10.1080/09291019009360031

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Male suprachiasmatic nuclei (SCN) lesioned, blinded rats were treated with chronic Methamphet‐amine (MA) via the drinking water. Body temperature, wheel running, food intake and drinking activity were automatically and continuously recorded. MA induced phase‐labile rhythms with periods outside the circadian range. The circadian rhythms in partially SCN‐lesioned rats reappeared without phase‐shifts upon withdrawal of one month of MA treatment. The MA‐induced rhythms persisted during food restriction and were synchronized by the time of food access. A phase shift of food access was followed by an immediate phase shift of the rhythms. These findings suggest that 1) the MA‐induced rhythms reflect an hourglass‐like oscillation 2) the SCN is not essential for their induction and 3) a cycle of food restriction acts as a Zeitgeber for this type of oscillation.

ISSN:0022-1945    

DOI:10.1080/09291019009360032

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

To study the reproductive and metabolic effects of circadian serotonergic and Dopaminergic activities, 5‐hydroxytryptophan (5‐HTP, serotonin precursor) and L‐dihydroxyphenylalanine (L‐DOPA, dopamine precursor) were administered daily in different temporal relationships in Red‐headed bunting (Emberiza bruniceps) during the preparatory phase of annual gonadal cycle. L‐DOPA given daily after 12 hours of 5‐HTP injection (12‐hr relationship) induced full gonadal development and fat deposition. But, L‐DOPA given after 4 hours of 5‐HTP administration (4‐hr relationship) stimulated only fat deposition without any gonadal effect. On the other hand, these two drugs injected 8‐hour apart led to significant decrease in gonadal growth as well as fat deposition.

ISSN:0022-1945    

DOI:10.1080/09291019009360033

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

The Indian palm squirrel,Funambulus pennantishowed a seasonal testicular cycle characterized by a short period of sexual quiescence with arrest of spermatogenesis in November when daylength and temperature were decreasing. The period of sexual recrudescence started from December when daylength and temperature were minimal and humidity was changing. The testes remained sexually active during rest of the annum.

ISSN:0022-1945    

DOI:10.1080/09291019009360034

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Simulations of thermoperiodic response curves for the insectsSarcophaga argyrostomaandDia‐traea grandiosellaare made, using a damped circadian oscillator model. Results compare well with experimental data for these species and demonstrate how an external coincidence model can account for thermoperiodic effects.

ISSN:0022-1945    

DOI:10.1080/09291019009360035

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291019009360028

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor