title: Gender differences in pain and biomechanical responses after acid sensitization of the human esophagus.
abstract: Our aims were to investigate gender differences to multimodal stimulations of the esophagus after experimentally induced sensitization. Thirty healthy age-matched subjects, 13 males and 17 females, were included. Pain evoked by mechanical and thermal stimuli was assessed before and after perfusion of the lower esophagus with 0.1 N hydrochloric acid. Males were more sensitive to the baseline mechanical stimuli (P < 0.01) and tolerated a lower volume of acid (P = 0.04). After acid perfusion, males were more sensitive than females to distensions (cross-sectional area P = 0.001 and volume P = 0.001). Acid perfusion sensitized both males (P = 0.03) and females (P = 0.04) to heat stimulation but not to cold stimulation (males, P = 0.09; females, P = 0.8). The referral areas for pain evoked by mechanical and thermal stimuli were larger in females compared with males both before and after acid perfusion (P = 0.002). In females only the referred pain area increased to heat stimulations (P = 0.02). Acid infusion resulted in a more hyperreactive esophagus (P = 0.03) but the hyperreactivity was not gender-dependent. In conclusion, males were more sensitive to mechanical and chemical esophageal stimuli and showed acid-evoked mechanical hyperalgesia. Females had significantly larger referred pain areas to the stimulations. The differentiated response to peripheral and central pain mechanisms may explain the gender-related differences seen in several gastrointestinal disorders.
authors.affiliation: Center for Biomechanics and Pain, University Hospital Aalborg, DK-9000, Aalborg, Denmark.
authors.forename: Hariprasad
authors.initials: H
authors.lastname: Reddy
authors.forename: Lars
authors.initials: L
authors.lastname: Arendt-Nielsen
authors.forename: Camilla
authors.initials: C
authors.lastname: Staahl
authors.forename: Jan
authors.initials: J
authors.lastname: Pedersen
authors.forename: Peter
authors.initials: P
authors.lastname: Funch-Jensen
authors.forename: Hans
authors.initials: H
authors.lastname: Gregersen
authors.forename: Asbjørn Mohr
authors.initials: AM
authors.lastname: Drewes
mesh_terms: D000328:Adult; D003080:Cold Temperature; D004947:Esophagus / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D010146:Pain / Q000139:chemically induced / Q000503:physiopathology*; D010147:Pain Measurement; D010812:Physical Stimulation; D012727:Sex Characteristics