Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.8 (cholinesterase)
 12,691 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Complete heart block was produced in eight dogs by the selective perfusion of physostigmine or neostigm into the atrioventricular (AV) node artery. A characteristic escape AV junctional rhythm emerged in each dog. After reversal of the cholinesterase paralysis with atropine, in each dog partial heart block was produced by an incision into the AV nodal region. In three of these eight dogs, a second incision placed slightly more anteriorly produced complete AV block which was followed by the emergence of an escape AV junctional rhythm similar to the one produced pharmacologically. Hearts of these three dogs were examined histologically with serial sections to determine the exact location of the incisions and their relationship to the AV node and His bundle. In each dog the incision that produced complete heart block passed directly through the junction of AV node with His bundle. In this region previous studies had demonstrated numerous P cells, which are thought to be the site of origin of normal cardiac automaticity. In each of the three hearts there were abundant P cells in continuity with the His bundle distal to the cut producing heart block. Significance of these findings is discussed relative to the locus of action of acetylcholine within the AV junction, the site of origin of AV junctional rhythm, and sme aspects of the experimental and therapeutic production of heart block.
 ...
PMID:Correlative electrophysiological and anatomical studies concerning the site of origin of escape rhythm during complete atrioventricular block in the dog. 44 92

The problem of development of the innervation of the rat atrioventricular node has been investigated by electron microscopy. Nerve bundles appear in relation to the node as early as the second postnatal day and vesiculated axons are seen throughout the entire node by the fourth day. Intimate contacts between nodal cells, axons and terminal varicosities are frequently observed. Use of the 5-hydroxydopamine tracer technique has enabled the identification of both cholinergic and adrenergic axons. It is concluded that the node has a dual innervation although cholinergic endings far outnumber those classified as adrenergic on the sixth postnatal day. These results are quite different to earlier findings made at the light microscope level and the discrepancies are discussed with respect to the histochemical techniques used. The suggestion that nodal differentiation is induced by nerves is considered in relation to the differences in cholinesterase activity exhibited by nodal cells during normal development and following neonatal sympathectomy.
 ...
PMID:The development of innervation in the rat atrioventricular node. 83 26

The conduction velocity and histological structure of motoneurons innervating normal and hypertrophied rat plantaris muscles were investigated. Hypertrophy was produced by ablation of synergist muscles. Single motor units were obtained by ventral root dissection and conduction velocities measured. The structure of neurons was investigated following retrograde labeling with horseradish peroxidase. A combined silver, gold and cholinesterase staining method was developed to study the motor endplate. In addition, the peripheral nerve was fixed, embedded in Araldite, and sectioned for determination of axonal size and myelin thickness. Conduction velocity of motor axons decreased following hypertrophy of the skeletal muscle (control CV = 75.8 +/- 8.9 m s-1, n = 94, hypertrophy CV = 69.0 +/- 12.3 m s-1, n = 84). However, no alteration in the size of motor axons or myelin thickness could account for this alteration in conduction velocity. Mean motoneuronal soma size decreased following muscle hypertrophy (soma diameter: control 36.1 +/- 4.6 microns, n = 283, hypertrophy 32.9 +/- 4.5 microns, n = 294). The complexity of the motor endplate increased following hypertrophy with an increased occurrence of nodal sprouts. In addition, the area of cholinesterase staining increased following hypertrophy (control 588.1 +/- 297.2 microns 2, n = 269, hypertrophy 857.7 +/- 357.0 microns 2, n = 269). This study found that both the morphological and physiological parameters of motoneurons innervating a hypertrophied muscle were shifted toward those of normal rat slow motor units.
 ...
PMID:Functional and structural changes of rat plantaris motoneurons following compensatory hypertrophy of the muscle. 199 79

Sartorius muscles of the frog Rana pipiens were used to study the incidence of motor nerve sprouting in normal unoperated muscles, in experimental muscles contralateral to axotomy of the sartorius nerve, and in sham-operated control muscles. Muscles were stained with either a combination of nitroblue tetrazolium nerve terminal stain and cholinesterase stain or with a combination of silver nerve terminal stain and cholinesterase stain. Each endplate that could be clearly seen was classified into one or more of the following categories: normal endplates without sprouts, three types of terminal sprouts, preterminal sprouts, nodal sprouts, sprouts of unknown origin and destination, and doubly innervated gutters. A quantitative study of 318 endplates from nine unoperated muscles, 779 endplates from 45 experimental muscles, and 694 endplates from 41 control muscles showed that all muscles had a high incidence of motor nerve sprouting and other forms of remodelling (20-28% of all endplates). There were, however, no significant differences between experimental, control, and unoperated muscles when results obtained with the same stains were compared. Results obtained with the two different stains were only slightly different. We conclude that sprouting is a very common but highly variable feature of normal frog neuromuscular junctions, and in the sartorius, contralateral axotomy does not alter this ongoing remodelling.
 ...
PMID:Motor axon sprouting in frog sartorius muscles is not altered by contralateral axotomy. 387 65

Morphologic features of the canine atrioventricular (AV) node were evaluated, using histochemical cholinesterase reactions and scanning electron microscopy. Three distinct regions of the AV node were observed: the transitional zone, superficial AV node, and deep AV node. The transitional zone lacked distinct cellular arrangement, and the cells were large and round with extensive branching on the ends. Superficial AV nodal cells were elongated, tightly packed, and smaller than were transitional cells. The superficial AV node was the densest zone of the AV node. Cell-to-cell contact was end-to-end. Deep AV nodal cells were long, formed laminated fascicles, were larger than the superficial AV nodal cells, and were continuous with the AV bundle.
 ...
PMID:Canine atrioventricular node: scanning electron microscopy and enzyme histochemistry. 395 8

A silver-cholinesterase stain is described which allows the visualization of the complete axonal tree, perineurial sheaths, motor nerve terminals and the cholinesterase at neuromuscular junctions throughout whole mounts of relatively thin muscles. The method is rapid, reliable and simple and allows the preservation of topographical information regarding both terminal and nodal sprouting in the whole muscle.
 ...
PMID:A method for visualizing axons and endplates throughout whole mounts of skeletal muscles using combined silver and cholinesterase stain. 617 69

Electrophysiological changes are correlated with pathological processes. Marked slowing of conduction is found in segmental demyelination due to delayed nodal excitation or short lengths of continuous conduction. Secondary demyelination causes slow conduction in hexacarbon neuropathy. Slight reduction in maximal conduction velocity is attributable to selective damage to large fibres in acrylamide neuropathy. Sensory nerve action potential amplitude is a sensitive measure of peripheral nerve function and comparison of abnormalities in different nerve segments may indicate the nature of the underlying pathological change. Other abnormalities may be elucidated by double stimuli; eg repetitive activity due to cholinesterase inhibition only occurs after the first of two closely spaced stimuli. Activity-related excitability changes may be detected by measuring the amplitude of the response to a submaximal stimulus at varying times after a maximal shock and is increased and prolonged by the pyrethroid deltamethrin.
 ...
PMID:Electrophysiological investigation of toxic neuropathies. 696 58