Effects of intravenous tryptophan infusion on thermoregulation in steers exposed to acute heat stress

Autor:	Madoka Sutoh, Etsuko Kasuya, Ken-ichi Yayou
Rok vydání:	2018
Předmět:	Male 0301 basic medicine Serotonin medicine.medical_specialty Hot Temperature medicine.medical_treatment Body Temperature 03 medical and health sciences Cerebrospinal fluid Stress Physiological Skin Physiological Phenomena Internal medicine medicine Animals Infusions Intravenous Saline Triiodothyronine Chemistry Rectum Tryptophan 0402 animal and dairy science Brain 04 agricultural and veterinary sciences General Medicine Thermoregulation 040201 dairy & animal science Heat stress 030104 developmental biology Endocrinology Cattle General Agricultural and Biological Sciences Respiration rate Body Temperature Regulation
Zdroj:	SC10201809030001 NARO成果DBa
ISSN:	1344-3941
Popis:	This study was conducted to investigate the effect of tryptophan (TRP) supply on the thermoregulatory responses via brain serotonin (5-HT) in cattle. In period 1, 12 Holstein steers were kept under a constant room temperature (22°C) and were administered the intravenous (i.v.) infusion of saline or TRP (38.5 mg/kg/2 h). Changes in rectal temperature (RT), 5-HT concentration in the cerebrospinal fluid (CSF), and other factors involved in thermoregulation were measured. In period 2, the steers received the same treatments as in period 1; however, the room temperature was elevated from 22°C to 33°C during i.v. infusion and maintained at 33°C for 3 h. 5-HT concentration in CSF increased following TRP infusion in both periods, and RT significantly decreased following TRP infusion only in period 2. The effect of TRP on respiration rate and plasma prolactin and total triiodothyronine concentrations was not significant. These results suggest that increase in TRP supply can attenuate increase in RT in response to acute heat stress through the increase in brain 5-HT, followed by presumable increase in evaporative heat loss from the skin surface in cattle. It is possible that the increase in peripheral blood TRP metabolites could also participate in the hypothermic effect of TRP.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b29f13011de9e6f04a1a1712ad62a861 https://doi.org/10.1111/asj.12988 Zobrazit plný text záznamu Plný text ve formátu PDF Plný text ve formátu HTML
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