piperidines and ibodutant

This review introduces the principles of visceral sensation and appraises the current approaches to management of visceral pain in functional GI diseases, principally IBS. These approaches include dietary measures including fibre supplementation, low fermentable oligosaccharides, disaccharides, monosaccharides and polyols diet, and pharmacological approaches such as antispasmodics, peppermint oil, antidepressants (tricyclic agents, selective serotonin reuptake inhibitors), 5-HT

Topics: Abdominal Pain; Anti-Infective Agents; Antidepressive Agents; Butyrophenones; Dipeptides; GABA Agents; Gastrointestinal Agents; Histamine H1 Antagonists; Humans; Imidazoles; Irritable Bowel Syndrome; Mentha piperita; Parasympatholytics; Phenylalanine; Piperidines; Plant Oils; Probiotics; Quaternary Ammonium Compounds; Rifamycins; Rifaximin; Serotonin 5-HT3 Receptor Antagonists; Thiophenes; Visceral Pain

We have characterized the pharmacological profile of the nonpeptide tachykinin NK2 receptor antagonist ibodutant (MEN15596) through radioligand binding and contractility assays in the human colon smooth muscle. The antagonist affinity of ibodutant was evaluated through concentration-dependent inhibition curves at the [(125)I]NKA specific binding by using membranes prepared from human colon smooth muscle. In this assay the affinity of ibodutant (pKi 9.9) was compared to that of other two selective NK2 receptor antagonists, nepadutant (pKi 8.4) and saredutant (pKi 9.2). The antagonist potency of ibodutant was evaluated towards the [βAla(8)]NKA(4-10)-mediated contractions of human colon smooth muscle strips. In this assay ibodutant (3, 10, 30 and 100 nM) induced a concentration-dependent rightward shift of the [βAla(8)]NKA(4-10) concentration-response curves without depressing the maximal contractile effect. The analysis of the curves yielded a Schild-plot linear regression with a slope not different from unity (1.02), thus indicating a surmountable antagonist behavior. The calculated apparent antagonist potency as pKB value was 9.1. No sex related differences were observed in NK2 receptor pharmacology for [βAla(8)]NKA(4-10) or ibodutant in colonic strips obtained from male or female patients. Reversibility experiments of tachykinin NK2 receptor blockade indicated that the inhibition of the agonist-induced contractions in preparations pre-exposed to ibodutant, and afterwards subjected to repeated washing cycles remained almost constant showing no sign of recovery during the 3h observation period. Overall, the present study indicates ibodutant as a potent tachykinin NK2 receptor antagonist in the human colon tissue, also endowed with a persistent duration of action.

Topics: Aged; Aged, 80 and over; Benzamides; Binding, Competitive; Colon; Dipeptides; Female; Humans; In Vitro Techniques; Male; Middle Aged; Peptides, Cyclic; Piperidines; Radioligand Assay; Receptors, Neurokinin-2; Thiophenes