Distinct localization of prokineticin 2 and prokineticin receptor 2 mRNAs in the rat suprachiasmatic nucleus

Jul 6, 2006The European journal of neuroscience

Different locations of prokineticin 2 and its receptor RNA in the rat brain’s body clock region

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Prokineticin 2 (PK2) mRNA levels in the rat suprachiasmatic nucleus (SCN) exhibit a robust circadian oscillation with peak expression during the day.

PK2 is highly expressed in the SCN, which regulates circadian rhythms in mammals.
rPK2 mRNA levels showed significant oscillation patterns under both light:dark and constant dark conditions.
More than 50% of neurons with rPK2 mRNA co-express either vasoactive intestinal peptide (VIP), gastrin-releasing peptide (GRP), or arginine vasopressin (AVP).
rPKR2 mRNA levels did not show significant changes throughout the day.
Neurons containing rPKR2 are primarily located in the dorsolateral SCN and do not co-express rAVP, rVIP, rGRP, or rPK2 transcripts.
The dorsolateral SCN region exhibited a delayed cycling of the rPer1 gene.

AI simplified

The suprachiasmatic nucleus (SCN) is the master circadian clock that regulates physiological and behavioral circadian rhythms in mammals. Prokineticin 2 (PK2) is highly expressed in the SCN, and its involvement in the generation of circadian locomotor activity has been reported previously. In the present study, using in situ hybridization methods, we investigated the localization of PK2 and prokineticin receptor 2 (PKR2), a specific receptor for PK2, in the rat SCN. In steady light : dark (L : D = 12 : 12 h) and constant dark conditions, rPK2 mRNA displayed a robust circadian oscillation with a peak occurring during the day. Moreover, during peak expression, the rPK2 mRNA-positive neurons were scattered in both the dorsomedial and ventrolateral SCN, which are two functionally and morphologically distinct subregions. Furthermore, double-labeling in situ hybridization experiments revealed that greater than 50% of the rPK2 mRNA-containing neurons co-expressed either vasoactive intestinal peptide (VIP), gastrin-releasing peptide (GRP) or arginine vasopressin (AVP) in the SCN. In contrast, the rPKR2 mRNA levels did not show significant diurnal alterations. rPKR2 mRNA-containing neurons were also clustered in the dorsolateral part of the SCN, which shows negligible labeling of either rAVP, rVIP, rGRP or rPK2 transcripts. In addition, this region exhibited a delayed cycling of the rPer1 gene. These results suggest an intrinsic PK2 neurotransmission and functionally distinct roles for PKR2-expressing neurons in the SCN.

Full Text

Full text is available at the source.

View full text ↗

Distinct localization of prokineticin 2 and prokineticin receptor 2 mRNAs in the rat suprachiasmatic nucleus

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief