A phase response curve for the locomotor activity rhythm of the rat

1978 ◽  
Vol 34 (12) ◽  
pp. 1602-1603 ◽  
Author(s):  
K. Honma ◽  
F. Katabami ◽  
T. Hiroshige
Keyword(s):  
Locomotor Activity ◽  
Response Curve ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Phase Response ◽  
Locomotor Activity Rhythm

Notizen: Weak and Strong Phase Shifting in the Activity Rhythm of Leucophaea maderae (Blaberidae)after Light Pulses of High Intensity

1977 ◽  
Vol 32 (5-6) ◽  
pp. 464-465 ◽  
Author(s):  
Gottfried Wiedenmann
Keyword(s):  
High Intensity ◽  
Response Curve ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Phase Response ◽  
Strong Phase ◽  
Light Pulses ◽  
Leucophaea Maderae ◽  
Running Activity ◽  
High Intensity Light

Abstract In the running activity of the cockroach Leucophaea maderae a strong phase response curve is found when using high intensity light pulses (80 000 lx and about 12 hours duration). The phase response curve has an unsymmetric shape: delays are larger than advances. The phase jump lies about 2 hours after subjective midnight.

Administering triazolam on a circadian basis entrains the activity rhythm of hamsters

1989 ◽  
Vol 256 (3) ◽  
pp. R639-R645
Author(s):  
O. Van Reeth ◽  
F. W. Turek
Keyword(s):  
Response Curve ◽  
Wheel Running ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Phase Relationship ◽  
Phase Shifts ◽  
Phase Response ◽  
Light Pulses ◽  
Circadian Time ◽  
Free Running

A single injection of the short-acting benzodiazepine, triazolam, can induce permanent phase shifts in the circadian rhythm of locomotor activity in free-running hamsters, with the direction and magnitude of the phase shifts being dependent on the circadian time of treatment. The shape of the "phase-response curve" to triazolam injections is totally different from that for light pulses. These findings raise the possibility that repeated injections of triazolam on a circadian basis might be capable of entraining the circadian pacemaker underlying the activity rhythm of hamsters and that the entrainment pattern might differ from that observed in animals entrained to light pulses. To test this hypothesis, blind hamsters received intraperitoneal injections of triazolam (or vehicle) every 23.34, 23.72, 24.00 or 24.66 h for 19-20 days, and the effect of these injections on the period of the rhythm of wheel-running behavior was determined during and after treatment. Repeated injections of 0.1 mg triazolam at these time intervals resulted in the entrainment of the activity rhythm in 36 of 40 animals, whereas 0 of 40 animals entrained to vehicle injections. Importantly, the phase relationship between triazolam injections and the circadian activity rhythm was dependent on the period of drug treatment and could be predicted from the phase-response curve to single injections of triazolam. These phase relationships are dramatically different from those observed between the activity rhythm and 1-h light pulses presented at similar circadian intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Phase-response and Aschoff illuminance curves for locomotor activity rhythm of the rat

1984 ◽  
Vol 246 (3) ◽  
pp. R299-R304 ◽  
Author(s):  
T. L. Summer ◽  
J. S. Ferraro ◽  
C. E. McCormack
Keyword(s):  
Locomotor Activity ◽  
Wheel Running ◽  
Phase Response Curve ◽  
Activity Rhythm ◽  
Continuous Light ◽  
Phase Response ◽  
Sprague Dawley ◽  
Continuous Darkness ◽  
Light Pulses ◽  
Log Steps

A phase-response curve (PRC) for the circadian rhythm of locomotor activity was constructed for female Sprague-Dawley-derived rats kept in continuous darkness (DD) except when given a 1-h light pulse (150 lx) once each 2 wk. By use of the circadian onset of wheel running as the phase-reference point, the free-running period (tau) in DD was 24.09 h. Maximum phase delays and phase advances occurred in response to light pulses given during the first 5 and last 6 h of activity, respectively. The delay-to-advance ratio (D/A) of the PRC was 1.5. In a separate group of rats exposed to continuous light, tau increased by 1.45 h as illuminance was increased in log steps from 0.1 to 10 lx, thus demonstrating the Aschoff effect in rats. This increase in tau was large, considering the relatively low D/A of the PRC, suggesting that factors in addition to the D/A contribute to the Aschoff effect.

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