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Region Hovedstaden - en del af Københavns Universitetshospital
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Photoperiodic co-regulation of kisseptin, neurokinin B and dynorphin in the hypothalamus of a seasonal rodent

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  1. Distribution and seasonal variation in hypothalamic RF-amide peptides in a semi-desert rodent, the jerboa

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  2. Mapping of kisspeptin fibres in the brain of the pro-oestrus rat

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  3. Characterization of the uptake of DADLE to isolated nerve terminals - morphine stimulates uptake

    Publikation: Bidrag til tidsskriftKonferenceartikelForskningpeer review

Vis graf over relationer

In many species, sexual activity varies on a seasonal basis. Kisspeptin (Kp), a hypothalamic neuropeptide acting as a strong activator of gonadotrophin-releasing hormone neurones, plays a critical role in this adaptive process. Recent studies report that two other neuropeptides, namely neurokinin B (NKB) and dynorphin (DYN), are co-expressed with Kp (and therefore termed KNDy neurones) in the arcuate nucleus and that these peptides are also considered to influence GnRH secretion. The present study aimed to establish whether hypothalamic NKB and DYN expression is photoperiod-dependent in a seasonal rodent, the Syrian hamster, which exhibits robust seasonal rhythms in reproductive activity. The majority of Kp neurones in the arcuate nucleus co-express NKB and DYN and the expression of all three peptides is decreased under a short (compared to long) photoperiod, leading to a 60% decrease in the number of KNDy neurones under photo-inhibitory conditions. In seasonal rodents, RFamide-related peptide (RFRP) neurones of the dorsomedial hypothalamus are also critical for seasonal reproduction. Interestingly, NKB and DYN are also expressed in the dorsomedial hypothalamus but do not co-localise with RFRP-immunoreactive neurones, and the expression of both NKB and DYN is higher under a short photoperiod, which is opposite to the short-day inhibition of RFRP expression. In conclusion, the present study shows that NKB and DYN display different photoperiodic variations in the Syrian hamster hypothalamus. In the arcuate nucleus, NKB and DYN, together with Kp, are down-regulated under a short photoperiod, whereas, in the dorsomedial hypothalamus, NKB and DYN are up-regulated under a short photoperiod.

OriginalsprogEngelsk
TidsskriftJournal of Neuroendocrinology
Vol/bind26
Udgave nummer8
Sider (fra-til)510-20
Antal sider11
ISSN0953-8194
DOI
StatusUdgivet - aug. 2014

ID: 44954037