Functional cardiac orexin receptors: role of orexin-B/orexin 2 receptor in myocardial protection.

ABSTRACT: Orexins/hypocretins exert cardiovascular effects which are centrally mediated. In the present study, we tested whether orexins and their receptors may also act in an autocrine/paracrine manner in the heart exerting direct effects. Quantitative reverse transcription-PCR (RT-PCR), immunohistochemical and Western blot analyses revealed that the rat heart expresses orexins and orexin receptors (OXR). In isolated rat cardiomyocytes, only orexin-B (OR-B) caused an increase in contractile shortening, independent of diastolic or systolic calcium levels. A specific orexin receptor-2 (OX2R) agonist ([Ala¹¹, d-Leu¹⁵]-Orexin B) exerted similar effects as OR-B, whereas a specific orexin receptor-1 (OX1R) antagonist (SB-408124) did not alter the responsiveness of OR-B. Treatment of

SUBMITTER: Patel VH 

PROVIDER: S-EPMC6365625 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature