Hypothalamic TRPV4 channels participate in the medial preoptic activation of warmth-defence responses in Wistar male rats

Author(s)

Scarpellini, Carolina da Silveira ^{[1, 2, 3]} ; Cristina-Silva, Caroline ^{[1, 2]} ; Biancardi, Vivian ^{[1, 2, 4]} ; Gargaglioni, Luciane H. ^[1] ; Almeida, Maria Camila ^[5] ; Bicego, Kenia Cardoso ^[1]

Affiliation

^[1] Sao Paulo State Univ, Coll Agr & Vet Sci, Dept Anim Morphol & Physiol, Via Acesso Prof Paulo Castellane S-N, BR-14884900 Jaboticabal, SP - Brazil

^[2] Joint UFSCar UNESP Grad Program Physiol Sci, BR-13565905 Sao Carlos, SP - Brazil

^[3] St Michaels Hosp, Keenan Res Ctr Biomed Sci, Toronto, ON M5B 1T8 - Canada

^[4] Univ Alberta, Fac Med & Dent, Dept Physiol, Edmonton, AB T6G 2R7 - Canada

^[5] Univ Fed ABC UFABC, Ctr Nat & Human Sci, BR-09606070 Sao Bernardo Do Campo, SP - Brazil

• Document type: Journal article
• Source: PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY; v. 471, n. 9, p. 1191-1203, SEP 2019.
• Web of Science Citations: 0

Abstract

Recently, we have described, in non-genetically modified rats, that peripheral transient receptor potential vanilloid-4 (TRPV4) channels are activated and trigger warmth-defence responses at ambient temperatures of 26-30 degrees C. Evidence points to the presence of TRPV4 in the medial preoptic area, a region described to be involved in the activation of thermoeffector pathways, including those involved in heat loss. Thus, we tested the hypothesis that TRPV4 in the medial preoptic area modulates thermoregulation under warm conditions. To this end, under two ambient temperatures (21 and 28 degrees C), body temperature was measured in rats following blockade of preoptic TRPV4 with two antagonists, HC-067047 and GSK 2193874. Oxygen consumption, heat loss index and preferred ambient temperature were also determined in order to assess thermoeffector activity. Antagonism of central TRPV4 caused an increase in body temperature in rats exposed to 28 degrees C, but not in those exposed to 21 degrees C. The body temperature increase at 28 degrees C was accompanied by an increase in oxygen consumption and an earlier reduction of the heat loss index. In behavioural experiments, control animals previously exposed to warm ambient temperatures (28-30 degrees C) for 2 h selected colder temperatures in a thermogradient compared to those injected with HC-067047. Our results support the idea that preoptic TRPV4 modulates thermoregulation in a warm environment by activating both autonomic and behavioural heat loss responses. Thus, according to the present study and to that published recently by our group, the activation of warmth-defence responses by TRPV4 seems to be dependent on the activity of both peripheral and central channels. (AU)

• FAPESP's process: 12/15298-2 - Cardiorespiratory pattern and awake-sleep state in male and female rats exposed to fluoxetine during prenatal period
• Grantee: Vivian Biancardi Rossato
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/04849-6 - Role of TRPV4 channels in thermoregulation in endotherms
• Grantee: Kênia Cardoso Bícego
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/19131-2 - Role of hypothalamic TRPV4 channels in activation/inhibition of autonomic thermoeffectors during fever and endotoxemic chock
• Grantee: Carolina da Silveira Scarpellini
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/17278-2 - ROLE OF THE RAPHE IN THE CONTROL OF THERMOEFECTORS IN PRECOCIOUS BIRDS
• Grantee: Caroline Cristina Silva
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 15/02991-0 - Involvement of TRPM8 channels in thermoregulation of Wistar rats
• Grantee: Maria Camila Almeida
• Support Opportunities: Regular Research Grants