Neurophysiological and Behavioural Analysis of Circadian Rhythm Entrainment
Abstract
We investigated neurotransmitters which play a role in conveying light information to the circadian clock in the suprachiasmatic nucleus (SCN). We studies the effects on SCN cell responses to light of classic small-molecule transmitters, such as glutamate, serotonin and acetylcholine, as well as a number of peptides. We showed that glutamate can affect SCN cell firing rates through both ionotropic and metabotropic receptors. We found that the peptides GRP and VIP also affect SCN in vivo with a pattern of temporal sensitivity similar to that of light. We studied how serotonin and melatonin alter photic responses of SCN cells, and showed that serotonin acts via a receptor that resembles the 5-HT7 subtype. We recently demonstrated differences in the responses to light of SCN neurons in nocturnal rodents compared to those is degus, a diumal/crepuscular rodent. In vivo and in vitro studies suggest the possibility that the inhibitory neurotransmitter GABA is found in the retinal entrainment route in both types of mammals, along with the excitatory transmitter glutamate. To facilitate our behavioural studies, we developed a data analysis system for dealing with activity rhythm data collected by computer.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 29, 2000
- Accession Number
- ADA376062
Entities
People
- Benjamin Rusak
Organizations
- Dalhousie University