Testing of visceral sensitivity.
Under normal circumstances most of the visceral input to the central nervous system is not perceived consciously. Visceral hypersensitivity associated with altered reflex activity seems to be a common pathophysiological mechanism in functional gastrointestinal disorders. Investigation of visceral sensitivity in humans is based on distension tests using barostat, or tensostat more recently. Tensostat may allow better standardization of distending stimuli, regardless of the capacity or compliance of the organ being tested. Other techniques include transmucosal electrical nerve stimulation, and chemical or thermal stimulation. Measurement of the responses to gut stimuli is based on the evaluation of conscious perception or objective responses, such as reflex activity or central processes. Recently, the assessment of the central responses has become available due to a variety of new brain imaging techniques. Several factors are thought to influence the results of visceral sensitivity studies: age, gender, physiological factors (postprandial testing) as well as psychological factors (stress, hypnosis, hypervigilance phenomenon). Technical conditions for performing tests like distension protocols may considerably affect the perception of sensory thresholds. Various mediators and pharmacological agents, in particular those acting on serotonin receptors, affect the sensory function of the gastrointestinal tract, and some of them have therapeutic potential in the treatment of visceral hypersensitivity.
Mulak
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Department of Gastroenterology and Hepatology, Wroclaw Medical University, Wroclaw, Poland. agata.mulak@wp.pl
D000818:Animals; D005767:Gastrointestinal Diseases / Q000175:diagnosis / Q000503:physiopathology; D041981:Gastrointestinal Tract / Q000294:innervation / Q000502:physiology; D006801:Humans; D012107:Research Design; D012684:Sensory Thresholds / Q000502:physiology; D017833:Visceral Afferents / Q000502:physiology*