scholarly journals Effect of Transplanting Suprachiasmatic Nuclei from Donors of Different Ages into Completely SCN Lesioned Hamsters

1993 ◽  
Vol 4 (4) ◽  
pp. 257-265 ◽  
Author(s):  
Claire M. Kaufman ◽  
Michael Menaker
Keyword(s):  
Vasoactive Intestinal Peptide ◽  
Suprachiasmatic Nucleus ◽  
Neural Tissue ◽  
Circadian Pacemaker ◽  
Suprachiasmatic Nuclei ◽  
Graft Success ◽  
Wheel Activity ◽  
Genetically Determined ◽  
Age Range ◽  
New Evidence

The suprachiasmatic nucleus (SCN) is the primary circadian pacemaker in mammals. Ralph and colleagues/14/provided recent new evidence for this by transplanting SCNs between golden hamsters with different genetically determined periods and producing circadian rhythmsof running wheel activity with periods characteristic of the donor. We have extended these studies in order to evaluate the age range of donor tissue that can be used for transplantation. SCN of hamsters from embryonic day 11 through postnatal day 12 can serve as functional grafts to restore rhythmicity to arrhythmic SCN lesioned animals. The time between SCN transplantation and onset of rhythmicity does not depend on the age of the donor. The presence of patches containing vasoactive intestinal peptide (VIP) immunoreactive cells is a good indicator of graft success, while its absence is correlated with a lack of transplant effect. The 18 day span during which SCN tissue can be harvested for transplantation should expand the uses to which this technique can be put. Our results also suggest that it would be advantageous to examine the age range of neural tissue that ca’n be used in other transplantation models.

scholarly journals The cell-autonomous clock of VIP receptor VPAC2 cells drives circadian behaviour

2020 ◽  
Author(s):  
Ryan Hamnett ◽  
Johanna E. Chesham ◽  
Elizabeth S. Maywood ◽  
Michael H. Hastings
Keyword(s):  
Vasoactive Intestinal Peptide ◽  
Suprachiasmatic Nucleus ◽  
Ex Vivo ◽  
Cell Types ◽  
Feedback Loops ◽  
Target Cells ◽  
Circadian Pacemaker ◽  
Circadian Period ◽  
Daily Rhythms ◽  
Cognate Receptor

AbstractCircadian (∼daily) rhythms pervade mammalian behaviour. They are generated by cell-autonomous, transcriptional/translational feedback loops (TTFL), active in all tissues. This distributed clock network is co-ordinated by the principal circadian pacemaker, the hypothalamic suprachiasmatic nucleus (SCN). Its robust and accurate time-keeping arises from circuit-level interactions that bind its individual cellular clocks into a coherent time-keeper. Cells that express the neuropeptide vasoactive intestinal peptide (VIP) mediate retinal entrainment of the SCN, and in the absence of VIP, or its cognate receptor VPAC2, circadian behaviour is compromised because SCN cells cannot synchronise. The contributions to SCN pacemaking and circadian behaviour of other cell types, not least the VPAC2-expressing target cells of VIP, are, however, not understood. We therefore employed intersectional genetics to manipulate the cell-autonomous TTFL of VPAC2-expressing cells, creating temporally chimaeric mice. We could then determine whether and how VPAC2-expressing cells (a minority ∼35% of SCN cells) contribute to SCN time-keeping. Lengthening of the intrinsic TTFL period of VPAC2 cells by deletion of the CK1εTau allele concomitantly lengthened the period of circadian behavioural rhythms. It also increased the variability of the circadian period of bioluminescent TTFL rhythms in SCN slices recorded ex vivo. Abrogation of circadian competence in VPAC2 cells by deletion of Bmal1 severely disrupted circadian behavioural rhythms and compromised TTFL time-keeping in the corresponding SCN slices. Thus, VPAC2-expressing cells are a distinct, functionally powerful subset of the SCN circuit, contributing to computation of ensemble period and maintenance of circadian robustness. These findings extend our understanding of SCN circuit topology.

Bronchiolitis as a Possible Cause of Wheezing in Childhood: New Evidence

PEDIATRICS ◽  
1984 ◽  
Vol 74 (1) ◽  
pp. 1-10
Author(s):  
Kenneth M. McConnochie ◽  
Klaus J. Roghmann ◽  
Suzanne J. Klein ◽  
Thomas K. Mclnery ◽  
James B. MacWhinney ◽  
...  
Keyword(s):  
Control Group ◽  
Historical Cohort ◽  
Practice Population ◽  
Confounding Variables ◽  
Significant Difference ◽  
History Of ◽  
Age Range ◽  
New Evidence ◽  
Possible Cause ◽  
Allergic Manifestations

A historical cohort study was performed in order to assess the hypothesis that even mild bronchiolitis in infancy is a predictor of wheezing later in childhood. Subjects who had experienced bronchiolitis and a matched control group were compared in terms of reported wheezing 8 years later. A highly significant difference was found between the bronchiolitis group and the control group in terms of current wheezing (P < .0001, relative risk 3.24). This difference was maintained after adjusting for many potentially confounding variables including family history of allergy and other allergic manifestations in the child. Results suggested that 13.6% of a normal practice population in the age range 6 to 9 years currently wheeze, but that 44.1% of children who experienced bronchiolitis currently wheeze. Based on the incidence of bronchiolitis (4.27/100 children in their first 2 years of life) and the relative odds for wheezing derived from a logistic regression model including variables that measured passive smoking, genetic tendency to wheeze, and bronchiolitis, calculations of attributable risk suggested that wheezing in 9.4% of the population of children who currently wheeze was attributable to bronchiolitis.

Developmental and Etiological Patterns of Substance Use from Adolescence to Middle Age: A Longitudinal Twin Study

2021 ◽  
Author(s):  
Stephanie Zellers ◽  
William G. Iacono ◽  
Matt McGue ◽  
SCOTT VRIEZE
Keyword(s):  
Substance Use ◽  
Middle Age ◽  
Common Factor ◽  
Latent Growth ◽  
Prospective Design ◽  
Time Average ◽  
Factor Modeling ◽  
Longitudinal Twin Study ◽  
Age Range ◽  
New Evidence

Background: Common liability to addiction framework suggests the tendency to use substances is largely a general heritable liability, but little is known about how expression of this liability varies from adolescence to middle age. We evaluated average trajectories of development and covariation underlying commonly used substances using a genetically informative prospective design spanning three decades. Methods: Using a sample of 3,762 twins across 7 prospective waves of assessment spanning ages 14-40, we modeled these relationships using two complementary approaches: common factor modeling and piecewise latent growth modeling with measures of alcohol, tobacco, and marijuana useResults: We found phenotypic (rp ~.3-.9) and genetic covariation (rg ~.3-1) between a single common factor at each age, though the factor explained less shared variance over time. Average substance use increased across adolescence for all phenotypes and either declined in adulthood or remained stable; these trajectories were heritable (~.35-.75) across all stages of development. We also found shared environmental covariation underlying growth model intercepts reflecting use at age 16 (rc ~.7-1). Conclusions: A heritable common factor accounted for co-occurring substance use from mid-adolescence to mid-adulthood, and greater substance specificity emerged with maturation. Similarly, all stages of substance use development were heritable, but correlations between substances weakened across development. These results extend and reinforce prior work examining consumption and problem use, providing new evidence over a broad age range showing that individuals use substances more indiscriminately at younger ages and show preferences later.

Chronic administration of methamphetamine does not affect the suprachiasmatic nucleus-operated circadian pacemaker in rats

1996 ◽  
Vol 208 (2) ◽  
pp. 129-132 ◽  
Author(s):  
Takahiro Moriya ◽  
Tatsuto Fukushima ◽  
Takao Shimazoe ◽  
Shigenobu Shibata ◽  
Shigenori Watanabe
Keyword(s):  
Suprachiasmatic Nucleus ◽  
Chronic Administration ◽  
Circadian Pacemaker

scholarly journals Vasoactive Intestinal Peptide Modulation of the Steroid-Induced LH Surge Involves Kisspeptin Signaling in Young but Not in Middle-Aged Female Rats

Endocrinology ◽  
2014 ◽  
Vol 155 (6) ◽  
pp. 2222-2232 ◽  
Author(s):  
Alexander S. Kauffman ◽  
Yan Sun ◽  
Joshua Kim ◽  
Azim R. Khan ◽  
Jun Shu ◽  
...  
Keyword(s):  
Vasoactive Intestinal Peptide ◽  
Suprachiasmatic Nucleus ◽  
Reproductive Age ◽  
Female Rats ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Middle Aged ◽  
Lh Surge ◽  
Young Females ◽  
Gnrh Neurons

Age-related LH surge dysfunction in middle-aged rats is characterized, in part, by reduced responsiveness to estradiol (E2)-positive feedback and reduced hypothalamic kisspeptin neurotransmission. Vasoactive intestinal peptide (VIP) neurons in the suprachiasmatic nucleus project to hypothalamic regions that house kisspeptin neurons. Additionally, middle-age females express less VIP mRNA in the suprachiasmatic nucleus on the day of the LH surge and intracerebroventricular (icv) VIP infusion restores LH surges. We tested the hypothesis that icv infusion of VIP modulates the LH surge through effects on the kisspeptin and RFamide-related peptide-3 (RFRP-3; an estradiol-regulated inhibitor of GnRH neurons) neurotransmitter systems. Brains were collected for in situ hybridization analyses from ovariectomized and ovarian hormone-primed young and middle-aged females infused with VIP or saline. The percentage of GnRH and Kiss1 cells coexpressing cfos and total Kiss1 mRNA were reduced in saline-infused middle-aged compared with young females. In young females, VIP reduced the percentage of GnRH and Kiss1 cells coexpressing cfos, suggesting that increased VIP signaling in young females adversely affected the function of Kiss1 and GnRH neurons. In middle-aged females, VIP increased the percentage of GnRH but not Kiss1 neurons coexpressing cfos, suggesting VIP affects LH release in middle-aged females through kisspeptin-independent effects on GnRH neurons. Neither reproductive age nor VIP affected Rfrp cell number, Rfrp mRNA levels per cell, or coexpression of cfos in Rfrp cells. These data suggest that VIP differentially affects activation of GnRH and kisspeptin neurons of female rats in an age-dependent manner.

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