Controlling the excitability of IPANs: a possible route to therapeutics.

Recent studies have shown that intrinsic primary afferent neurons (IPANs) express a much larger range of ionic currents than non-sensory neurons of the enteric nervous system. These ionic currents can be modulated by neurotransmitters that are synaptically released onto the soma (unlike cranial and spinal sensory neurons). The membrane receptors and ionic channels that are involved in the sensory transduction processes of IPANS are beginning to be defined. IPANS can move between a large range of excitability states that are influenced by neurotransmitters and hormones. An additional cause of variability in excitability is the actions of inflammatory mediators. It is becoming apparent that the variation in excitability of IPANS might play a critical role in determining the physiological state of the intestine.