An insect acetylcholinesterase inhibitor from compound eyes ofTriatoma infestans (Hemiptera)

Summary The presence of an acetylcholinesterase inhibitor in the compound eyes of adultTriatoma infestans was demonstrated. The inhibitory activity was localized in the ocular pigments separated by disc gel electrophoresis. The inhibitor was selective against insect acetylcholinesterase, reversible, noncompetitive and heat stable.This work was supported by a research grant from the Comisión de Investigaciones Cientificas de la provincia de Buenos Aires, Argentina.     

Actions d'un inhibiteur sélectif des acétylcholinestérases,le 3318 CT,sur la transmission neuromusculaire du chat

Summary 3318 CT [bis (piperidinomethylcoumaranyl-5) cetone dimethiodide], a specific inhibitor of acetylcholinesterase, antagonizes, in small dosages, the neuromuscular block induced by Flaxedil in the cat; in larger dosages, 3318 CT blocks the transmission: this paralysing action is not related to an accumulation of acetylcholine, as acetylcholine itself antagonizes it; decamethonium also restores, partially at least, the indirect contractions. Prostigmine and m-hydroxyphenyltrimethylammonium have no action. The neuromuscular block by 3318 CT thus appears as a competitive curarization in an animal with inhibited acetylcholinesterases. There was no indication that pseudo-cholinesterase can play a part in the neuromuscular transmission; whereas in the case of the vagal transmission such a possibility could not be ruled out.     

Histochemical remarks on monoamine oxidase and acetylcholinesterase in some regions of amphibian brain

Summary The histochemical localization of monoamine oxidase and acetylcholinesterase has been studied in the cerebellum, optic tectum and telencephalon of three amphibian species. For acetylcholinesterase in particular, different histochemical methods and selective inhibitors have been used in order to investigate the actual nature of enzymatic activity revealed.     

Effect of pentobarbital on the synaptosomal activity of acetylcholinesterase in Mongolian gerbils

Summary The influence of Na pentobarbital anesthesia on the activity of specific and nonspecific cholinesterase was studied in the synaptosomal fraction of Mongolian gerbils' brains. These studies have shown that this barbiturate inhibits the specific activity of acetylcholinesterase only.     

Effect of pentobarbital on the synaptosomal activity of acetylcholinesterase in Mongolian gerbils

The influence of Na pentobarbital anesthesia on the activity of specific and nonspecific cholinesterase was studied in the synaptosomal fraction of Mongolian gerbils' brains. These studies have shown that this barbiturate inhibits the specific activity of acetylcholinesterase only.     

Eyestalks control of diurnal rhythm of acetylcholinesterase activity in the crabOziotelphusa senex senex

Summary The crab (Oziotelphusa) displays a diurnal rhythm of acetylcholinesterase activity, with maximal activity around midnight, alternating with minimal activity at noon. Bilateral eyestalk ablation eliminates the diurnal rhythm of acetylcholinesterase activity.Acknowledgments. We wish to express our gratitude to CSIR, New Delhi for providing financial support to PSR. Reprint requests should be addressed to Prof. R. Ramamurthi.     

Subcellular distribution of acetylcholinesterases in the neural lobe of the bovine pituitary gland

Summary Biochemical analysis of subcellular fractions of bovine neural lobe tissue indicated that non-specific acetylcholinesterase was principally associated with the pituicytes.     

Effect of orchidectomy and estradiol on acetylcholinesterase activity in rat brain areas and adenohypophysis

Orchidectomy plus estradiol administration decreased acetylcholinesterase activity in the rat cerebral cortex and mesencephalon, while in the amygdala it was increased. In the adenohypophysis, orchidectomy increased enzyme activity, but subsequent estradiol treatment decreased it. The hypothalamus did not respond to either manipulation.     

Effect of orchidectomy and estradiol on acetylcholinesterase activity in rat brain areas and adenohypophysis

Summary Orchidectomy plus estradiol administration decreased acetylcholinesterase activity in the rat cerebral cortex and mesencephalon, while in the amygdala it was increased. In the adenohypophysis, orchidectomy increased enzyme activity, but subsequent estradiol treatment decreased it. The hypothalamus did not respond to either manipulation.     

Calcium and magnesium deficiency-induced atrophy of muscle and calcium accumulation in the spinal cord

After severe dietary calcium-magnesium deficiency in rats, succinic dehydrogenase and acetylcholinesterase enzyme activity of gastrocnemius muscle showed a neurogenic atrophy. This alteration was associated with a high concentration of calcium in the spinal cord.     

Localisation of acetylcholinesterase in rat myotubes in the presence of beta-endorphin and beta-endorphin-(1-27)

In rat embryo skeletal myotubes, acetylcholinesterase is present, as multiple forms, and can be detected in deposits at the cell surface. Myotubes cultured in the presence of beta-endorphin, exhibit an increased predominance of the globular (precursor) forms of the enzyme, which are largely restricted to intracellular sites associated with nuclei. In the presence of beta-endorphin-(1-27), the relative proportions of the different forms of acetylcholinesterase is similar to that seen in the controls, but the enzyme is intracellular and has a characteristic focal localisation in the myotube.     

Diethylmesoxalate hydrate, a new irreversible inhibitor of cholinesterases.

Bovine erythrocyte acetylcholinesterase and human plasma cholinesterase are irreversibly inhibited by diethylmesoxalate hydrate, the inhibition potency being comparable to that of certian insecticidal organophosphates and carbamates. Insect cholinesterases, however, appear to be much less affected by diethylmesoxalate hydrate. The compound was also found to inhibit the hydrolysis of paraoxon by rabbit plasma A-esterase, but in a reversible mode.     

The acetylcholinesterase reaction and catecholamine fluorescence in the glomus cells of rat carotid body

Summary The presence of both acetylcholinesterase reaction and glyoxylic acid-induced fluorescence of catecholamines in the same glomus cells of rat carotid body was demonstrated using combined histochemical methods. A suggestion is made that the glomus cells have both excitatory and inhibitory effects on the chemosensory nerve via acetylcholine and catecholamines, respectively.Acknowledgments. The present study was supported by grants from the Emil Aaltonen Foundation and the Finnish Cancer Foundation to Timo Waris.     

Diethylmesoxalate hydrate,a new irreversible inhibitor of cholinesterases

Summary Bovine erythrocyte acetylcholinesterase and human plasma cholinesterase are irreversibly inhibited by diethylmesoxalate hydrate, the inhibition potency being comparable to that of certain insecticidal organophosphates and carbamates. Insect cholinesterases, however, appear to be much less affected by diethylmesoxalate hydrate. The compound was also found to inhibit the hydrolysis of paraoxon by rabbit plasma A-esterase, but in a reversible mode.     

Effects of later isolation housing on both scent marking behavior and brain cholinergic activites in Mongolian gerbils

Summary Significant difference in the frequency of marking was found between aggregated and isolated gerbils. As compared with the aggregated gerbils, isolated gerbils showed high acetylcholinesterase activity in the hippocampus and high choline acetyltransferase activity in the hypothalamus.The authors are indebted to Dr Masaru Sorimachi of the Department of Physiology. Ehime University, for pertinent advices and professional assistance in radiochemical assay.     

The size of motor units in laryngeal muscles of the rat

Summary The size of motor units in rat laryngeal muscles was determined by correlating the number of neurons labeled by i.m. injections of horseradish peroxidase with the number of motor end plates stained for acetylcholinesterase. The cricothyroid has a motor unit size of 8 muscle fibers per motor neuron and the posterior cricoarytenoid 4–5 muscle fibers per motor neuron.     

Comparative study of the sensitivity of acetylcholinesterases and cholinesterases from animal and bacterial sources to inhibition by serotonin and its derivatives.

Serotonin was found to inhibit human erythrocyte and electric-eel acetylcholinesterase activities. The serotonin amino group, free of negative charges in its vicinity and its hydroxyl group, were important for the inhibition. Serotonin precursors and several related compounds had little or no effect. Human plasma cholinesterase was also inhibited by serotonin and tryptamine. In contrast to these animal enzymes, the cholinesterase of Pseudomonas aeruginosa was refractory to serotonin and its derivatives under the same experimental conditions.     

Preferential neurotoxicity of pentobarbital on nerve and glial cells in culture

The effect of pentobarbital was studied in a mixed population of nerve and glial cells dissociated from brains of 7-day chick embryos and maintained in culture. Pentobarbital-Na was added in various concentrations ranging from 5 X 10(-5) M to 1 X 10(-3) M. The neuronal density was monitored by counting the neurons, neuronal identity was established by staining for Nissl Bodies and acetylcholinesterase. Over a culture period of 3 weeks, it was found that the barbiturate exerts a preferential dose-dependent cytotoxic effect on neurons.