title: Face cooling-induced reduction of plasma prolactin response to exercise as part of an integrated response to thermal stress.
abstract: This study was designed to verify if the decrease in blood prolactin (PRL) induced by selective face cooling during exercise could be part of a response to specific body thermal stress. Five healthy trained male cyclists presenting a significant plasma PRL elevation to exercise were, on three occasions and at weekly interval, submitted to a submaximal exercise (approx. 65% VO2max) on ergocycle with and without selective face cooling. In absence of face cooling a first trial served to establish reference values for workload, heart rate and plasma PRL levels, the latter increasing markedly (450% of resting values) in these conditions. On a second trial but with workload maintained at reference values (222 +/- 9 W), a significant bradycardia was observed with face cooling; furthermore, plasma PRL response to exercise was significantly reduced (to 31% of original response). On a third trial with face cooling, workload had to be significantly augmented (242 +/- 10 W) to maintain heart rate at reference level (78% HRmax); in addition, plasma PRL response to exercise was almost unchanged compared to the reference-value level. The absence of a significant face cooling-induced decrease in sympathetic tonus, as evaluated through peripheral plasma catecholamines response, does not indicate a role for the autonomic nervous system in the face cooling-induced reduction of both heart rate and PRL responses during exercise. Assay of circulating peripheral beta-endorphins could indicate that the face cooling-induced PRL blunted response does not necessarily involve an opioid mediation.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Institut National de la Recherche Scientifique (INRS-Santé), Pointe-Claire Québec, Canada.
authors.forename: G R
authors.initials: GR
authors.lastname: Brisson
authors.forename: P
authors.initials: P
authors.lastname: Boisvert
authors.forename: F
authors.initials: F
authors.lastname: Péronnet
authors.forename: A
authors.initials: A
authors.lastname: Quirion
authors.forename: L
authors.initials: L
authors.lastname: Senécal
mesh_terms: D000328:Adult; D001831:Body Temperature; D002395:Catecholamines / Q000097:blood; D003080:Cold Temperature; D005080:Exercise Test; D006339:Heart Rate; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008297:Male; D009638:Norepinephrine / Q000097:blood; D005082:Physical Exertion; D011388:Prolactin / Q000097:blood*; D011863:Radioimmunoassay; D013312:Stress, Physiological; D013696:Temperature; D013997:Time Factors; D014691:Ventilation; D001615:beta-Endorphin / Q000097:blood
chemical_list: D002395:Catecholamines; D001615:beta-Endorphin; D011388:Prolactin; D009638:Norepinephrine