Sex-related differences in sweat gland cholinergic sensitivity exist irrespective of differences in aerobic capacity.
Mechanisms accounting for sex-related differences in the sweat response remain to be elucidated. In the present study, we focused on differences in sweat gland cholinergic sensitivity between males and females. Since, males usually possess higher aerobic capacity than females, we investigated sweating in males and females grouped according to aerobic capacity (.VO(2peak)). Forty-four subjects were assigned to four groups: males with higher (MH) and lower (ML), and females with higher (FH) and lower (FL) .VO(2peak). Forearm sweating was induced by iontophoretic administration (1.5 mA, 60 muA cm(-2), 5 min) of pure water or varying concentrations of pilocarpine hydrochloride (0.125, 0.250, 0.5, 1.0 and 2.0%). Local sweat rate (absorbent paper) and the number of activated sweat glands (iodine impregnated paper) were computed. Maximal pilocarpine-induced sweat rate (SR(max)) and the pilocarpine concentration which elicited 50% of maximal sweating response (K (m)) were calculated. Sweat rate and active gland density increased in response to greater doses of pilocarpine (p < 0.05). Inter-group differences were evident: SR(max) was greatest for MH and lowest for FL (p < 0.05), but no significant differences were observed between ML and FH (p = 0.24). Higher SR(max) were observed, within-sex, for those with greater aerobic capacity (p < 0.05). Furthermore, males' K (m) values were higher than females', indicating greater sweat gland affinity for pilocarpine even for groups having similar aerobic capacity (p < 0.05). In summary, we confirmed that the human sudomotor response is affected by aerobic capacity but, also, that sex-related differences in sweat gland cholinergic sensitivity exist and are not necessarily associated with the typical differences in .VO(2peak) observed between sexes.
Madeira
Luciana Gonçalves
LG
Laboratório de Fisiologia do Exercício, Departamento de Educação Física, Universidade Federal de Minas Gerais, Av. Carlos Luz 4664, Belo Horizonte, MG, Brazil. lgmadeira@hotmail.com
da Fonseca
Michele Atalla
MA
Fonseca
Ivana Alice Teixeira
IA
de Oliveira
Kenya Paula
KP
Passos
Renata Lane de Freitas
RL
Machado-Moreira
Christiano Antônio
CA
Rodrigues
Luiz Oswaldo Carneiro
LO
D000328:Adult; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D018721:Muscarinic Agonists / Q000494:pharmacology*; D010101:Oxygen Consumption; D010862:Pilocarpine / Q000494:pharmacology*; D012737:Sex Factors; D013545:Sweat Glands / Q000187:drug effects* / Q000502:physiology; D013546:Sweating / Q000187:drug effects*; D055815:Young Adult
D018721:Muscarinic Agonists; D010862:Pilocarpine