Yahashi, Satowa Kang, Ki Sung Kaiya, Hiroyuki Matsuda, Kouhei 2024-01-20T15:03:14Z 2024-01-20T15:03:14Z 2021-09-05 2012-04 0196-9781 https://pubs.kist.re.kr/handle/201004/129374 Ghrelin was first identified and characterized from rat stomach as an endogenous ligand for the growth hormone secretagogue (GHS) receptor (GHS-R). Ghrelin also acts as an orexigenic factor and regulates energy balance in rodents. In goldfish, native ghrelin consists of 11 molecular variants, the major form being a 17-residue peptide with n-octanoic acid modification (n-octanoyl ghrelin17), and intraperitoneal (IP) administration of n-octanoyl ghrelin17 induces central actions such as stimulation of food intake and suppression of locomotor activity through capsaicin-sensitive afferents. Four types of GHS-Rs (1a-1, 1a-2, 2a-1 and 2a-2) have been identified in goldfish, and one GHS, GHRP-6, can activate only GHS-R2a-1 in vitro. However, there is no information about the effect of GHRP-6 on food intake and locomotor activity in goldfish in vivo. Therefore, in the present study, we examined whether IP-administered GHRP-6 would mimic the orexigenic action of n-octanoyl ghrelin17 and its suppression of locomotor activity. IP administration of GHRP-6 at 1 pmol/g body weight (SW) stimulated food intake, and was equipotent to the orexigenic action of n-octanoyl ghrelin17 at 10 pmol/g BW. IP-injected GHRP-6 at 1 pmol/g BW also induced a significant decrease of locomotor activity, as was the case for IP-injected n-octanoyl ghrelin17 at 10 pmol/g BW. The action of GHRP-6 was blocked by IP-preinjected capsaicin at 160 nmol/g BW. These results suggest that the central action of GHRP-6 might be mediated via the GHS-R2a-1-signaling pathway, and subsequently through capsaicin-sensitive afferents in goldfish. (C) 2012 Elsevier Inc. All rights reserved. English ELSEVIER SCIENCE INC GROWTH-HORMONE CDNA CLONING PROLACTIN-RELEASE ACYLATED PEPTIDE RAINBOW-TROUT GHS-R PURIFICATION RECEPTOR TILAPIA ACID GHRP-6 mimics ghrelin-induced stimulation of food intake and suppression of locomotor activity in goldfish Article 10.1016/j.peptides.2012.01.025 1 PEPTIDES, v.34, no.2, pp.324 - 328 PEPTIDES 34 2 324 328 scie scopus 000303181600007 2-s2.0-84859424263 Biochemistry & Molecular Biology Endocrinology & Metabolism Pharmacology & Pharmacy Biochemistry & Molecular Biology Endocrinology & Metabolism Pharmacology & Pharmacy Article GROWTH-HORMONE CDNA CLONING PROLACTIN-RELEASE ACYLATED PEPTIDE RAINBOW-TROUT GHS-R PURIFICATION RECEPTOR TILAPIA ACID Capsaicin Vagal afferent Food intake Goldfish Ghrelin GHRP-6 GHS GHS-R GHS-R2a-1 Locomotor activity n-Octanoyl ghrelin17