Effects of Intranasal Oxytocin on Thermal Pain in Healthy Men: A Randomized Functional Magnetic Resonance Imaging Study. Issue 2 (February 2015)

• Record Type: Journal Article
• Authors: Zunhammer, Matthias; Geis, Sandra; Busch, Volker; Greenlee, Mark W.; Eichhammer, Peter
• Is Part Of: Psychosomatic medicine. Volume 77:Issue 2(2015)
• Publication Date: 2015-02
• Subjects: intranasal oxytocin -- experimental pain -- functional magnetic resonance imaging -- amygdala -- human -- BOLD = blood oxygen level dependent -- CSF = cerebrospinal fluid -- FWE = family-wise error -- fMRI = functional magnetic resonance imaging -- IU = international units -- MRI = magnetic resonance imaging -- POMS = Profile of Mood States -- QST = Quantitative Sensory Testing -- ROI = region of interest -- SPM = statistical parametric mapping -- VAS = visual analog scale; Medicine, Psychosomatic -- Periodicals; 616.0805
• DOI: 10.1097/PSY.0000000000000142
• Languages: English
• ISSNs: 0033-3174

Abstract

ABSTRACT: Objective: Intranasal oxytocin has been shown to affect human social and emotional processing, but its potential to affect pain remains elusive. This randomized, placebo-controlled, double-blind, crossover trial investigated the effect of intranasal oxytocin on the perception and processing of noxious experimental heat in 36 healthy male volunteers. Methods: Thermal thresholds were determined according to the Quantitative Sensory Testing protocol. A functional magnetic resonance imaging experiment including intensity and unpleasantness ratings of tonic heat was used to investigate the effects of oxytocin within the brain. Results: Thirty men (aged 18–50 years) were included in the study. Intranasal oxytocin had no significant effect on thermal thresholds, but significantly ( t = −2.06, p = .046) reduced heat intensity ratings during functional magnetic resonance imaging. The effect on intensity ratings was small (−3.46 points on a 100-point visual analog scale [95% confidence interval {CI} = −6.86 to −0.07] and independent of temperature. No effects of oxytocin on stimulus- or temperature-related processing were found at the whole-brain level at a robust statistical threshold. A region of interest analysis indicated that oxytocin caused small but significant decreases in left (−0.045%, 95% CI = −0.087 to −0.003, t = −2.19, p = .037) and right (−0.051%, 95% CI = −0.088 to −0.014], t = −2.82, p = .008) amygdala activity across all temperatures. Conclusions: The present study provides evidence for a significant but subtle inhibitory effect of oxytocin on thermal stimulus ratings and concurrent amygdala activity. Neither of the two effects significantly depended of temperature; therefore, the hypothesis of a pain-specific effect of oxytocin could not be confirmed. Trial Registration: EUDRA-CT 2009-015115-40 Abstract : Supplemental digital content is available in the text.