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Investigating the role of substance P in photic responses of the circadian system: Individual and combined actions with gastrin-releasing peptide
- Source :
- Neuropharmacology. 58:277-285
- Publication Year :
- 2010
- Publisher :
- Elsevier BV, 2010.
-
Abstract
- The suprachiasmatic nucleus (SCN) contains the master mammalian circadian pacemaker. It is comprised of several phenotypically distinct cell groups, some of which are situated in the weakly rhythmic retinoresponsive ventrolateral region while others are found in the rhythmic, non-retinoresponsive dorsomedial region. The mechanism by which retinorecipient cells convey photic information to the dorsomedial clock cells is unclear. The ventrolateral SCN core contains a variety of cell phenotypes. Two neuropeptides, namely substance P (SP) and gastrin-releasing peptide (GRP) extensively colocalize with calbindin D28K, a marker for SCN cells that are strongly light-responsive. Previous studies have implicated these neuropeptides in photic phase shifting of the circadian system. The present study examines how these peptides interact to regulate photic responses of the circadian system. It was observed that 55.5 +/- 9.1% of SP cells colocalized GRP. SP did not enhance GRP-induced phase shifts in the early-subjective night, while it significantly attenuated GRP-induced phase shifts during the late-subjective night. SP induced significant phase shifts that did not resemble light in the early-subjective night, but was not necessary for light-induced phase shifts and Fos expression at this time. SP induced significant Fos expression only in the late subjective night. SP may not be a necessary component in the pathway(s) involved in photic phase shifting during the early-subjective night, but may modulate phase shifts during the late-subjective night. Distinct biochemical mechanisms that underlie behavioral phase shifts may account for the differences observed in the early- vs. late-subjective night.
- Subjects :
- Male
medicine.medical_specialty
Neuropeptide
Substance P
Biology
Cellular and Molecular Neuroscience
chemistry.chemical_compound
Gastrointestinal Agents
Cricetinae
Internal medicine
Gastrin-releasing peptide
Gene expression
medicine
Animals
Drug Interactions
Circadian rhythm
Pharmacology
Analysis of Variance
Neurotransmitter Agents
Mesocricetus
Suprachiasmatic nucleus
Colocalization
Circadian Rhythm
Cell biology
Oncogene Proteins v-fos
Endocrinology
Gastrin-Releasing Peptide
Gene Expression Regulation
chemistry
Photic Stimulation
Intracellular
Subjects
Details
- ISSN :
- 00283908
- Volume :
- 58
- Database :
- OpenAIRE
- Journal :
- Neuropharmacology
- Accession number :
- edsair.doi.dedup.....f92db1d0b87c58d6331bd8d96a9ba8c6