عنوان

A test of the serotonin hypothesis of nonphotic phase shifting of the Syrian hamster circadian system

Number

TLpq304481918

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

A test of the serotonin hypothesis of nonphotic phase shifting of the Syrian hamster circadian system

General Material Designation

[Thesis]

First Statement of Responsibility

M. C. Antle

Subsequent Statement of Responsibility

R. E. Mistlberger

Name of Publisher, Distributor, etc.

Simon Fraser University (Canada)

Date of Publication, Distribution, etc.

1998

Specific Material Designation and Extent of Item

89

Dissertation or thesis details and type of degree

M.A.

Body granting the degree

Simon Fraser University (Canada)

Text preceding or following the note

1998

Text of Note

In the Syrian hamster, the daily rhythm of activity can be reset by activity experimentally induced during the mid-day, which is the usual rest phase in nocturnal rodents. These non-photically induced phase shifts may be mediated, in whole or in part, by serotonergic input to the circadian pacemaker, located in the suprachiasmatic nuclei (SCN). This hypothesis is based on evidence that serotonin agonists can phase shift behavioural rhythms in vivo, and SCN electrophysiological rhythms in vitro. However, evidence that serotonin lesions or antagonists can prevent activity-induced phase shifts is weak or lacking. The present experiment was designed to further test this serotonin hypothesis of non-photic entrainment. Hamsters were given 3 hour wheel confinement tests, to induce activity, following treatment with various selective and non-selective serotonin antagonists, or their vehicles, delivered synthetically or centrally. Metergoline, WAY100135, and Ritanserin did not attenuate the resulting phase shifts from induced activity. NAN190 did significantly attenuate the resulting phase shift, but this effect was confounded with an attenuation of the induced activity. This study failed to support the position that serotonergic activity within the SCN is necessary for the production of non-photic phase shifts. The receptor ligands selected are active primarily at 5-HT1A/7 receptors, as previous studies suggest that these are the most likely receptors to mediate phase shifting of the SCN pacemaker by serotonin. However, it remains possible that a novel type of serotonin receptor may mediate the effects of serotonin and behavioral stimuli on circadian phase.

Anatomy & physiology

Animals

Biological sciences

Health and environmental sciences

Neurology

Pharmacology

M. C. Antle

R. E. Mistlberger

Electronic name

p

[Thesis]

276903

a

Y