A novel TRPV1 receptor antagonist JNJ-17203212 attenuates colonic hypersensitivity in rats.

This study examined the efficacy of a novel TRPV1 antagonist, JNJ-17203212, in two experimental rat models that exhibit a hypersensitive visceral motor response (VMR) to colorectal distension (CRD). In the first model, intraluminal administration of acetic acid (1% solution) into the distal colon produced an acute colonic hypersensitivity. In the second model, intraluminal administration of 2,4,6-trinitrobenzenesulfonic acid (TNBS) into the distal colon produced a chronic, post-inflammatory colonic hypersensitivity 30 days post-TNBS administration.

Increased colonic transit in rats produced by a combination of a cholinesterase inhibitor with a 5-HT4 receptor agonist.

Increased cholinergic stimulation and accelerated gastrointestinal (GI) transit may be produced by direct stimulation of the acetylcholine (ACh) receptor with an appropriate agonist by increased release of ACh from cholinergic nerve terminals or by a decreased removal or breakdown of ACh within cholinergic synapses. The acetylcholinesterase inhibitor, neostigmine, and the 5-HT(4) receptor partial agonist tegaserod, are two agents with known prokinetic activity which work by different mechanisms that result in increased levels of ACh at cholinergic synapses innervating intestinal smooth muscle. Here, we aimed to investigate the potential synergistic effect on colonic transit that may occur with concomitant use of these two agents.

5-HT2B receptors do not modulate sensitivity to colonic distension in rats with acute colorectal hypersensitivity.

The 5-HT4 receptor agonist tegaserod is an effective prokinetic agent that increases gastrointestinal secretion and reduces visceral sensitivity. Tegaserod has both 5-HT4 receptor agonist and 5-HT2B receptor antagonist activity, the latter being a less potent effect of the drug. In a rat model of colonic hypersensitivity, selective 5-HT4 receptor antagonists only partially reversed the antihyperalgesic effect of tegaserod suggesting that non-5-HT4 receptor-mediated mechanisms may also be involved in its overall antihyperalgesic action.