Modulation of Iris Sphincter and Ciliary Muscles by Urocortin 2

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Tavares Silva, M (Author) FMUP; Ferreira, D (Author) FMUP; Cardoso, S (Author) Other; Raimundo, AR (Author) Other; Barbosa Breda, J (Author) FMUP; Leite-Moreira AF (Author) FMUP; Rocha-Sousa A (Author) FMUP

Journal

Title: Physiological Research

Vol. 67

Pages: 465-474

ISSN: 0862-8408

Publisher: Akademie Ved Ceske Republiky

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 2 Citations

Other information

Authenticus ID: P-00P-2TC

DOI: 10.33549/physiolres.933646

Abstract (EN): Urocortin 2 (UCN2) is a peptide related to corticotropin-releasing factor, capable of activating CRF-R2. Among its multisystemic effects, it has actions in all 3 muscle subtypes. This study's aim was to determine its potential role in two of the intrinsic eye muscle kinetics. Strips of iris sphincter (rabbit) and ciliary (bovine) muscles were dissected and mounted in isometric force transducer systems filled with aerated-solutions. Contraction was elicited using carbachol (10(-6) M for iris sphincter, 10(-5) M for ciliary muscle), prior adding to all testing substances. UCN2 induced relaxation in iris sphincter muscle, being the effect maximal at 10(-7) M concentrations (-12.2 % variation vs. control). This effect was abolished with incubation of indomethacin, antisauvagine-30, chelerytrine and SQ22536, but preserved with L-nitro-L-arginine. In carbachol pre-stimulated ciliary muscle, UCN2 (10(-5) M) enhanced contraction (maximal effect of 18.2 % increase vs. control). UCN2 is a new modulator of iris sphincter relaxation, dependent of CRF-R2 activation, synthesis of prostaglandins (COX pathway) and both adenylate cyclase and PKC signaling pathways, but independent of nitric oxide production. Regarding ciliary muscle, UCN2 enhances carbachol-induced contraction, in higher doses.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10