Ketamine is one of the most widely-used “dissociative anesthetics”. It has been primarily known as an NMDA receptor antagonist with a potent anesthetic effect, but it can also interact with many other receptors and ion channels, such as opioid receptors, nicotinic acetylcholine receptors, muscarinic receptors and voltage-gated Ca2+ channels. Since the use of general anesthesia during surgical procedures is associated with multiple side effects including postoperative ileus due to inhibition of intestinal motility, we aimed to investigate the effects of ketamine on the muscarinic cation current termed mICAT, which underlies cholinergic excitation-contraction coupling of visceral smooth muscles. mICAT is mainly mediated by TRPC4 channels, which are activated in synergy by two muscarinic receptor subtypes, M2 and M3 [1, 2]. Experiments were performed on single ileal myocytes freshly isolated using collagenase from the longitudinal layer of the mouse ileum dissected from BALB/c two month-old male mice. mICAT was recorded in the whole-cell configuration of the patch-clamp techniques at room temperature (22-25 0C) using symmetrical Cs+ containing (125 mM) solutions with [Ca2+]i ‘clamped’ at 100 nM (10 mM BAPTA/4.6 mM CaCl2 mixture). Values are means±S.E.M., differences evaluated using Student’s t-test. Ketamine (100 μM, clinical concentration) suppressed mICAT induced by carbachol (CCh, 50 μM) by 62.4±2.6% within 3 min. Thus, maximal current densities at -40 mV were -15.1±3.3 pA/pF in control vs. -5.5±0.9 pA/pF in the presence of 100 μM ketamine (n=6, p<0.05). The IC50 value was estimated at 3.4 μM. The inhibitory effect was practically irreversible after ketamine wash-out. Remarkably, ketamine-suppressed mICAT could be completely recovered after application of TRPC4 agonist (-)-englerin A. In these experiments, amplitude of normalized mICAT activated by 50 μM CCh at -40 mV was -13.0±2.9 pA/pF in control, it decreased to -7.1±1.5 pA/pF in the presence of ketamine, but increased to -35.7±8.3 pA/pF after 10 nM (-)-englerin A application (n=5; p<0.01). These data define TRPC4 cation channel and signalling pathways leading to its activation during cholinergic excitation of intestinal myocytes as novel important targets for the inhibitory action of ketamine, while offering a strategy for current recovery by TRPC4 agonist (-)-englerin A.