The influence of the 5-HT3 receptor antagonist tropisetron on pain in
fibromyalgia: a functional magnetic resonance imaging pilot study.

Scand J Rheumatol Suppl. 2004(119):24-7.

Koeppe C, Schneider C, Thieme K, Mense S, Stratz T, Muller W, Flor H.

Department of Neuropsychology, University of Heidelberg, Central Institute
of Mental Health, Mannheim, Germany.

PMID: 15515408


OBJECTIVE: Central pain processing is altered in patients with fibromyalgia
syndrome (FMS). The serotonin metabolism, especially the 5-HT3 receptor,
seems to play an important role.

METHODS: We investigated the effect of the local injection of the 5-HT3
receptor antagonist tropisetron on the perception and central processing of
pain in FMS patients using painful mechanical stimulation and functional
magnetic resonance imaging (fMRI) within the framework of a
pre-/posttreatment double-blind design.

RESULTS: In the contralateral primary somatosensory cortex, contralateral
posterior insula, and anterior cingulate cortex, we found that the
activation was significantly reduced after treatment. On average, patients
rated the stimulation-induced pain intensity as stronger in the session
after treatment compared to before treatment, although the individual data
revealed a heterogeneous pattern. All patients showed sensitisation during
the painful stimulation, which was not influenced by the treatment.

CONCLUSIONS: Both the sensory-discriminative and motivational-affective
components of pain as measured by fMRI were altered by tropisetron.