PROK1 and irritable bowel syndrome: PK1 and prokineticin receptor 1 (PKR1) also mediate signal transduction in visceral hypersensitivity by participating in the regulation of gastrointestinal motility in IBS rats [25]; PKR1 knockout rats show Bv8-mediated hyperalgesia, weakened response to noxious heat stimuli, and reduced sensitivity to heat and mechanical stimulation [25].