title: Electrocutaneous pain thresholds are higher during systole than diastole.
abstract: Arterial baroreceptors may modulate pain. Evidence suggests the neurophysiological correlates of pain are dampened during systole, when baroreceptors are stimulated, compared to diastole, when stimulation is minimal. However, the influence of the cardiac cycle on perception of pain remains unclear. This study examined pain thresholds in 49 healthy adults at seven intervals after the R-wave of the electrocardiogram, using an interleaved up-down staircase procedure. Electrocutaneous stimuli were delivered to the hand and participants indicated the presence or absence of pain. Pain thresholds were higher mid-cycle, indicative of pain attenuation during systole compared to diastole. Moderation analyses revealed no relationship between the magnitude of cardiac cycle-related modulation and tonic blood pressure. These findings suggest fluctuations in arterial baroreceptor activity across the cardiac cycle may influence pain in normotensive individuals; however, tonic blood pressure may not affect the magnitude of this pain modulation.
authors.affiliation: Centre for Global Health and Human Development, School of Sport, Exercise and Health Sciences, Loughborough University, UK.
authors.forename: Mary
authors.initials: M
authors.lastname: Wilkinson
authors.forename: David
authors.initials: D
authors.lastname: McIntyre
authors.forename: Louisa
authors.initials: L
authors.lastname: Edwards
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology; D003971:Diastole / Q000502:physiology; D004558:Electric Stimulation / Q000009:adverse effects*; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010146:Pain / Q000503:physiopathology*; D017288:Pain Threshold / Q000502:physiology*; D012867:Skin / Q000503:physiopathology*; D013599:Systole / Q000502:physiology
keywords: Baroreceptor; Blood pressure; Cardiac cycle; Pain threshold