Journal
CHRONOBIOLOGY INTERNATIONAL
Volume 19, Issue 2, Pages 345-360Publisher
TAYLOR & FRANCIS INC
DOI: 10.1081/CBI-120002876
Keywords
suprachiasmatic nucleus; circadian rhythms; pineal gland; body temperature; behavioral state
Categories
Funding
- NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE [R01NS016304] Funding Source: NIH RePORTER
- NINDS NIH HHS [NS-16304] Funding Source: Medline
Ask authors/readers for more resources
The circadian timing system has three principal components: (i) entrainment pathways, (ii) pacemakers, and (iii) efferent pathways from the pacemakers that convey the circadian signal to effector systems. The suprachiasmatic nucleus (SCN) of the hypothalamus is the principal mammalian circadian pacemaker and, although we understand the organization of entrainment pathways to the SCN and the pacemaker itself we know much less about the functional organization of SCN projections mediating control of effector systems. It is unclear, for example, whether specific subsets of SCN projections control specific effector systems. In this study, we analyzed the effects of lesions ablating the paraventricular hypothalamic nucleus (PVH), with variable extension into the subparaventricular zone (SPVZ) and adjacent structures, on nocturnal pineal melatonin production and rhythms in core body temperature (T-b) and rest-activity (R-A). In accordance with prior work, ablation of the PVH abolishes the nocturnal rise in pineal melatonin. Lesions restricted to the PVH do not affect rhythms in T-b and R-A but lesions extending caudally and ventrally into the SPVZ disrupt the R-A rhythm proportionate to the interruption of caudal SCN projections without affecting the rhythm in T-b. We conclude that pacemaker regulation of the circadian rhythms analyzed in this study is mediated by discrete sets of SCN projections: (i) dorsal projections to the PVH control pineal melatonin production; (ii) rostral projections to the anterior hypothalamic/preoptic areas mediate the T-b rhythm; and (iii) caudal projections to the SPVZ and hypothalamic arousal systems located in the posterior and lateral hypothalamic areas control the rhythm in R-A.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available