Pauliukonis AC, Buenaventura C, Cline MA, Gilbert ER. Anorexigenic effects of substance P in Coturnix japonica.
Neuropeptides 2020;
81:102045. [PMID:
32220396 DOI:
10.1016/j.npep.2020.102045]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/15/2020] [Accepted: 03/18/2020] [Indexed: 11/18/2022]
Abstract
Substance P (SP) is an 11-amino acid tachykinin-related peptide that has anorexigenic effects in birds and mammals although the central mechanism is not well understood. Hence, the objective was to identify appetite-associated hypothalamic mechanisms in Japanese quail (Coturnix japonica). Seven days post-hatch, quail were intracerebroventricularly injected with 0, 0.25, 0.5 or 1.0 nmol of SP and monitored for 180 min. On a cumulative basis, quail that received 0.5 and 1.0 nmol of SP consumed less food for 90 min post-injection. On a non-cumulative basis, food intake was reduced in 0.5 nmol-injected birds at 30 min post-injection. Water intake was not affected. A comprehensive behavior analysis was performed, revealing that SP-injected chicks displayed less feeding pecks and reduced locomotion compared to vehicle-injected birds. To identify molecular mechanisms, the hypothalamus was isolated at 1 h post-injection and real-time PCR was performed to measure mRNA. Agouti-related peptide (AgRP) mRNA was reduced in SP-injected chicks. Immunohistochemistry was used to quantify c-Fos-expressing cells in appetite-associated hypothalamic nuclei. There were more reactive cells in the lateral hypothalamus (LH) and the paraventricular nucleus (PVN) of SP- than vehicle-injected chicks. The LH and PVN were collected for gene expression analysis. Corticotropin-releasing factor (CRF) and urotensin 2 (UTS2) mRNAs were greater in SP- than vehicle-injected chicks in the PVN. In the LH, CRF receptor sub-type 2 (CRFR2) mRNA was greater and kappa opioid receptor mRNA was reduced in SP- compared to vehicle-injected quail. Thus, SP induces a potent anorexia in quail that coincides with increased LH-specific CRFR2 mRNA and increased UTS2 mRNA in the PVN. Future studies will evaluate whether SP-induced anorexigenic effects are mediated through CRF receptors.
Collapse