Secretion of acetylcholinesterase and butyrylcholinesterase from the guinea‐pig isolated ileum

Abstract

Strips of longitudinal muscle from guinea‐pig ileum, retaining Auerbach's plexus, were superfused with oxygenated Krebs solution. Addition of 50 mm KCl led to a pronounced Ca2+‐dependent increase in the activities of both acetylcholinesterase and non‐specific cholinesterase (butyrylcholinesterase) in the perfusate but with no change in lactate dehydrogenase activity. No release of acetylcholinesterase, either spontaneous or K+‐evoked was observed in tissue freed of the nerve plexus, although release of butyrylcholinesterase still occurred. Carbachol induced a marked Ca2+‐dependent increase in the release of acetylcholinesterase but had no effect on the release of butyrylcholinesterase or lactate dehydrogenase. This carbachol‐evoked increase in acetylcholinesterase release was blocked by hexamethonium but not by atropine. Four readily soluble molecular forms of acetylcholinesterase and three soluble molecular forms of butyrylcholinesterase were present in innervated longitudinal muscle strips, but insignificant amounts of acetylcholinesterase were detected in denervated strips of muscle. Only one of the four molecular forms of acetylcholinesterase was recovered in the perfusates. It is concluded that acetylcholinesterase is secreted from the nerves of Auerbach's plexus in response to depolarizing stimuli or to nicotinic cholinergic stimulation, while butyrylcholinesterase is secreted from non‐neural elements, possibly the longitudinal muscle cells, of guinea‐pig ileum in response to a depolarizing stimulus.

Cholinesterase Its significance in anaesthetic practice

“…They claim that neurotransmitter hydrolysis may be controlled via two enzymatic pathways: the primary system is acetylcholinesterase for the acetylcholine, which is held in the synaptic cleft and the secondary system, using plasma cholinesterase, for the extraneuronal acetylcholine which has diffused into the smooth muscle regions. This physiological finding agrees with the anatomical findings of Appleyard & Smith [13] who found that the acetylcholinesterase was present in Auerbach's plexus of a guinea-pig's ileum whereas the plasma cholinesterase was detected mainly in the smooth muscle.…”

Regulation of Gastric Electrical and Mechanical Activity by Cholinesterases in Mice

“…AChE inhibitors decrease metabolism of ACh released from enteric neurons. 26 Blocking metabolism of ACh increases the availability of ACh and probably the effective distance over which ACh can diffuse from excitatory nerve terminals to affect postjunctional receptors. A result of preserving ACh in the tunica muscularis should be enhanced binding of muscarinic receptors that exert ionotropic and chronotropic effects in gastric muscles.…”

In vitro Interactions Between the Oral Absorption Promoter, Sodium Caprate (C10) and S. typhimurium in Rat Intestinal Ileal Mucosae

“…Apical fluids were sampled at regular intervals after tissue mounting and extracellular LDH levels were measured using an enzyme assay kit (Sigma, Poole, Dorset, UK) adapted for isolated intestinal tissue enzyme release (32). The percent cytotoxicity was determined by comparing the amount of extracellular LDH observed in the apical chamber to the maximum releasable LDH induced by exposure to 0.01% Triton-X-100.…”