Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.1.7 (acetylcholinesterase)
28,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stimulation of extrinsic nerves markedly alters pancreatic endocrine and exocrine secretion, yet little is known of the neurochemical organization and physiologic roles of specific neural pathways within the pancreas. Here we report histochemical staining for acetylcholinesterase (AChE), NADPH-diaphorase (NADPH-d), nitric oxide synthase (NOS), and several neuropeptides to identify the neurotransmitter content of rabbit pancreatic nerves. An extensive network of AChE-positive nerve fibers was found throughout the islets, acini, ducts, ganglia, and blood vessels. All pancreatic neurons were AChE positive, two thirds were NADPH-d positive, and many were NOS positive. Ganglia in the head/neck region were connected to the duodenal myenteric plexus by AChE- and NADPH-d-positive fibers, and NADPH-d-positive pancreatic neurons appeared to send processes toward both the duodenum and pancreas. Many pancreatic neurons were vasoactive intestinal peptide (VIP) positive, and VIP nerve terminals were abundant in ganglia, acini, islets, and ducts. Pituitary adenylate cyclase-activating peptide (PACAP-38)-positive fibers also were observed within acini and passing through ganglia. Substance P (SP)-, calcitonin gene-related peptide (CGRP)-, and dopamine beta-hydroxylase (DBH)-positive fibers were abundant along blood vessels and ducts, and varicose fibers were observed in pancreatic ganglia. Fine galanin-positive fibers were also occasionally observed running with blood vessels and through ganglia. Thus the rabbit pancreas receives a dense, diverse innervation by cholinergic, adrenergic, and peptidergic nerves and cholinergic pancreatic neurons, most also containing VIP or NOS or both, appear to innervate both endocrine and exocrine tissue, and may mediate local communication between the duodenum and pancreas.
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PMID:Morphology and histochemistry of the rabbit pancreatic innervation. 988 61

The carbamate pesticide, aldicarb, demonstrates significant acute toxicity in mammals, birds, and fish, and is readily biotransformed by most organisms studied. Metabolic products of aldicarb include the more toxic sulfoxide and the less toxic sulfone as two of the major products. Both the cytochrome P450 (CYP) and the flavin monooxygenase systems (FMO) are involved in this process. This study examined the capacities of liver microsomes of male channel catfish (Ictalurus punctatus), which lack FMO, to biotransform aldicarb in vitro. In addition, the acetylcholinesterase inhibitory potencies of aldicarb and its sulfoxide and sulfone derivatives were determined. For metabolism studies, incubations of [14C]-aldicarb (0.1mM) were carried out for up to 15-90 min using 1.0 mg/mL of hepatic microsomal protein. Total NADPH- dependent biotransformation was low (< 3.0% conversion to polar metabolites), and was inhibited by carbon monoxide. The only metabolite detected was aldicarb sulfoxide (Kmapp = 53.8 +/- 25.3 microM; Vmaxapp = 0.040 +/- 0.007 nmol/min/mg). Treatment of fish with the CYP modulators beta-naphthoflavone (BNF, 50 mg/kg) and ethanol (EtOH, 1.0% aqueous) had no effect on sulfoxide production. No correlation existed between CYP isoform expression (determined by western blot) and aldicarb sulfoxidation rates, suggesting the involvement of an unmeasured CYP isoform or involvement of several isoforms with low specificity. This study indicates that a low rate of bioactivation of aldicarb to aldicarb sulfoxide may be responsible for the resistance of channel catfish to aldicarb toxicity relative to that of other piscine species.
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PMID:In vitro sulfoxidation of aldicarb by hepatic microsomes of channel catfish, Ictalurus punctatus. 1033 Jun 85

This in vitro study was designed to identify the enzyme(s) involved in the two major metabolic pathways of rokitamycin [formations of leucomycin A7 (LMA7) from rokitamycin and of leucomycin V (LMV) from LMA7] and to assess possible drug interactions using human liver microsomes. Formation of LMA7 or LMV was NADPH-independent. Anti-rat NADPH cytochrome P-450 (CYP) reductase serum, specific inhibitors, or substrates of CYP isoforms showed no effects on the formation of LMA7 or LMV. The mean Vmax and Vmax/Km for the formation of LMA7 from rokitamycin were much greater (P <.01) than those for the formation of LMV from LMA7. Two esterase inhibitors, bis-nitro-phenylphosphate and physostigmine (100 microM), inhibited the formation of LMA7 or LMV by more than 85%, whereas no appreciable inhibition occurred by several substrates of carboxylesterase (EC 3.1.1.1). Except the moderate inhibition produced by promethazine and terfenadine, theophylline, mequitazine, chlorpheniramine, and diphenhydramine showed little or no inhibition for the formation of LMA7 or LMV. Rokitamycin, LMA7, LMV, erythromycin, and clarithromycin (up to 500 microM) had no appreciable inhibition for CYP1A2-, 2C9-, and 2D6-mediated catalytic reactions. However, rokitamycin, LMA7, erythromycin, and clarithromycin inhibited the CYP3A4-catalyzed triazolam alpha-hydroxylation with IC50 (Ki) values of 5.8 (2.0), 40, 33 (20), and 56 (43) microM, respectively. It is concluded that the formations of LMA7 from rokitamycin and of LMV from LMA7 are catalyzed mainly by human esterase enzyme [possibly cholinesterase (EC3.1.1.8)]. However, whether rokitamycin would inhibit the CYP3A-mediated drug metabolism in vivo requires further investigations in patients.
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PMID:An in vitro study on the metabolism and possible drug interactions of rokitamycin, a macrolide antibiotic, using human liver microsomes. 1038 20

Nitric oxide (NO) is a free radical gas that has been found to be produced in neuronal cells by the action of the enzyme brain nitric oxide synthase (bNOS). The aim of this study was to identify NO-containing nerve structures in the human nasal mucosa by localizing bNOS and to find out whether NO production is attached to the parasympathetic system. For this purpose, immunocytochemistry with antibodies to bNOS and neurofilament was performed. Additionally, nicotinamide-adenine dinucleotide phosphate diaphorase (NADPH-d), an enzyme that correlates with the localization of NO synthase, and acetylcholinesterase were visualized in a histochemical double staining technique on frozen sections. The NADPH-d and bNOS reactions were found in axons of nerve bundles and in subepithelial, glandular, and vascular nerve fibers. Arteries showed a distinctly developed nitric innervation, whereas no activity was found in nerve fibers supplying veins. A high coexistence of NADPH-d in parasympathetic nerves could be detected. These findings suggest that NO takes part in the nerve control functions of the human nasal mucosa.
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PMID:Histochemical and immunocytochemical study of nitrergic innervation in human nasal mucosa. 1052 78

This in-vitro study was designed to identify the enzyme(s) involved in the major metabolic pathway of rokitamycin, i.e. the formation of leucomycin A7, and to assess possible interactions of the drug with rat liver microsomes. Formation of leucomycin A7 was NADPH-independent and was not appreciably inhibited by anti-rat NADPH cytochrome P-450 reductase serum or cimetidine, a nonspecific inhibitor of cytochrome P-450 isoforms. Eadie-Hofstee plots for the formation of leucomycin A7 were indicative of apparently monophasic behaviour for six rat liver microsomes tested. The mean (+/- s.d.) kinetic parameters, Km, Vmax and Vmax/Km, for the formation of leucomycin A7 from rokitamycin were 47+/-13 microM, 390+/-56 nmol min(-1) (mg protein)(-1) and 8.6+/-1.6 mL min(-1) (mg protein)(-1), respectively. Three esterase inhibitors (100 microM), bis-nitrophenylphosphate, physostigmine and metrifonate inhibited the formation of leucomycin A7 by more than 60%. Metabolism of rokitamycin was inhibited by terfenadine, but not by mequitazine, whereas chlorpheniramine and theophylline activated the formation of leucomycin A7. Rokitamycin, leucomycin A7, leucomycin V, erythromycin and clarithromycin were weak inhibitors of CYP3A-catalysed 3-hydroxylation of quinine with mean IC50 values ranging from 71 to >100 microM. It is concluded that in rat liver microsomes the formation of leucomycin A7 from rokitamycin is catalysed mainly by an esterase (possibly cholinesterase, EC3.1.1.8), but not by cytochrome P-450 enzyme(s). Although in this in-vitro animal study CYP3A activity was barely inhibited by rokitamycin, the possibility cannot be totally discounted in man when rokitamycin is co-administered with drugs metabolized by CYP3A.
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PMID:An in-vitro study on the metabolism of rokitamycin and possible interactions of the drug with rat liver microsomes. 1057 88

Preliminary findings of a study on the role of oxidative stress in the developmental neurotoxicity of chlorpyrifos (CPF) indicates that in vitro exposure to 1-100 microM CPF or 1-100 nM CPF-oxon had no effect on the activity of glutathione peroxidase (GSHpx) in brain homogenates from postnatal day (PN) 21 rats, or on the activity of purified GSHpx. A single high-dose acute injection of 45 mg/kg CPF to PN19 rats also did not significantly alter GSHpx activity at PN21, in spite of extensive (72%) brain acetylcholinesterase (AChE) inhibition. However, catalase activity was significantly reduced by 28%. PN21 pups exposed maternally to a lower effective dose of CPF throughout development (dams injected with 50 mg/kg every 3 days) also had normal GSHpx activity, but a 30% increase in H2O2-independent NADPH consumption. Brain catalase activity in these rats was significantly increased by 24%. These preliminary data suggest that specific GSHpx activity is not altered by in vitro or in vivo exposures to CPF-oxon or CPF, but catalase and an unknown H2O2-independent NADPH-consuming factor were affected differentially depending on the type and timing of exposure.
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PMID:In vitro and in vivo effects of chlorpyrifos on glutathione peroxidase and catalase in developing rat brain. 1079 93

The freely diffusible radical, nitric oxide (NO), has been assumed to act as a retrograde signaling molecule that modulates transmitter release. Acetylcholine (ACh) is known to function as a typical neurotransmitter. In the present work we have examined the presence of both transmitters (NO and ACh) and their possible relations in the rabbit spinal cord. In our experiments we have used histochemical methods for the visualization of acetylcholinesterase (AChE) and NADPH diaphorase (NADPH-d) which label neurons that express nitric oxide synthase (NOS). Both histochemical methods were performed separately or together on the same sections of the thoracic spinal cord. NADPH-d positive dark blue stained neurons were seen mostly in superficial and deep layers of the dorsal horn, preganglionic autonomic neurons and pericentral area. The presence of AChE positive amber yellow neurons was confirmed mostly in motoneurons located in the ventral horns and in neurons of the pericentral and intermediate zone. Besides the above mentioned neurons, also double-labeled neurons were found which contained both the yellow and dark blue histochemical product. Their presence was confirmed in the intermediate zone and in the pericentral area. Thus, the co-existence of NADPH-d and AChE occurred in the location of interneurons. Our observations suggest that NO may play a role in the control of cholinergic neuronal activity and that NO can be involved in the modulation of synaptic transmission.
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PMID:Partial colocalization of NADPH-diaphorase and acetylcholinesterase positivity in spinal cord neurons. 1080 17

Nitric oxide (NO) plays a major role as a neuronal messenger molecule. NO has been assumed to act as a retrograde signalling molecule that modulates transmitter release. Acetylcholine (ACh) is known to function as a typical neurotransmitter. In the present work the presence of both transmitters (NO and ACh) and their possible relations in the rabbit spinal cord were examined. In our experiments histochemical methods for the visualisation of acetylcholinesterase (AChE) and NADPH diaphorase (NADPH-d) were used. Both histochemical methods were performed separately and together on the same sections of the thoracic spinal cord. NADPH-d positive dark blue stained neurons were mainly detected in superficial and deep layers of dorsal horn, preganglionic autonomic neurons and pericentral area (1). The presence of AChE positive amber yellow neurons was confirmed mostly in motoneurons located in ventral horns and then in neurons of the intermediate zone. Except for the above mentioned also double-labeled neurons containing both yellow and dark blue histochemical product were noticed. Their presence was confirmed in the intermediate zone and in the pericentral area. Thus, the coexistence of NADPH-d and AChE was confirmed in the area of interneurons. These observations suggest that NO may play a role in the control of cholinergic neuronal activity and that NO can be involved in the modulation of synaptic transmission. (Fig. 9, Ref. 21.)
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PMID:[Coexistence of cholinergic and nitrergic neurotransmitters in the spinal cord of rabbits]. 1082 7

The cyto- and chemoarchitecture of basal forebrain cholinergic neurons (BFCN) was investigated in the lower primate, the common marmoset (Callithrix jacchus). A large population of magnocellular, hyperchromic, and choline acetyltransferase (ChAT)-positive neurons was detected in the marmoset basal forebrain. The distribution of these neurons was similar to those in higher primates. Thus, ChAT-positive neurons were observed in the medial septum (Ch2), the vertical (Ch2) and horizontal (Ch3) limbs of the diagonal band of Broca, and the nucleus basalis of Meynert (Ch4). The Ch4 complex was relatively well differentiated and displayed distinct sectors. We detected anterior (Ch4a, with a medial and a lateral subdivision), intermediate (Ch4i, with a dorsal and a ventral subdivision), and posterior (Ch4p) sectors in the marmoset Ch4. The Ch4i was relatively small while the Ch4p was large. Similar to the rodent, the marmoset Ch1 extended quite a distance posteriorly, and the Ch4p displayed a major interstitial component distributed within the globus pallidus, its medullary laminae, and the internal capsule. Virtually all of the marmoset BFCN displayed acetylcholinesterase activity, and low affinity (p75(NTR)) and high affinity (Trk) neurotrophin receptor immunoreactivity. A majority contained immunoreactivity for calbindin-D(28K) and calretinin. Many of the Ch4 neurons also displayed tyrosine hydroxylase immunoreactivity. The BFCN lacked galanin immunoreactivity, but were innervated by galanin-positive fibers. None of the marmoset BFCN were NADPH-d-positive. Thus, the BFCN display major anatomical and biochemical differences in the marmoset when compared with higher primates. The marmoset BFCN also display many characteristics common to other primates. This fact, combined with the relatively short life span of the marmoset, indicates that this species may be ideal for studies of age-related changes in the BFCN.
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PMID:Cyto- and chemoarchitecture of basal forebrain cholinergic neurons in the common marmoset (Callithrix jacchus). 1099 91

The motility of the avian oviduct is controlled by hormones and neurons, but little is microscopically known about a neural network in the oviduct. The present study was investigated to determine the distribution of nitric oxide-synthesizing neurons in the oviduct of the pigeon by histochemistry for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d). The NADPH-d reaction was seen in the neurons and fibers. NADPH-d neurons were mainly distributed around the arterioles of the intermuscular tissue in the upper oviduct (infundibulum, magnum, and isthmus); in addition, NADPH-d neurons were also seen in the smooth muscle layers and lamina propria in the lower oviduct (uterus and vagina). NADPH-d neurons were found singly or in small groups of two-eight cell bodies. The number of NADPH-d neurons was smallest in the infundibulum, gradually increased toward the vagina. NADPH-d was also shown to be strongly positive in many neurons in the ganglia of the vaginal adventitia. Bundles of NADPH-d fibers ran in the smooth muscle layer, surrounded blood vessels, or connected with small groups of NADPH-d neurons by forming strands. Thin fibers branched from these bundles and constituted a finer network in the smooth muscle layer and lamina propria. Acetylcholinesterase staining in neurons and fibers showed a similar pattern of NADPH-d distribution in the oviduct. By double staining, 70 approximately 77% of neurons showed colocalization of NADPH-d and acetylcholinesterase in the uterus and vagina. Tyrosine hydroxylase immunoreactivity stained only nerve fibers and were distributed largely around blood vessels in the oviduct. Nerve fibers immunoreactive for calcitonin-gene related peptide, galanin, methionine-enkephalin, substance P, or vasoactive intestinal peptide were found sparsely in the oviduct. These results demonstrate that nitrergic neurons make up a large subpopulation of intrinsic neurons that are closely associated with a cholinergic system in the pigeon oviduct, thus suggesting that nitric oxide and acetylcholine could be used to modify the relaxation of the avian oviduct.
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PMID:Innervation of the pigeon oviduct: correlation of NADPH diaphorase with acetylcholinesterase, tyrosine hydroxylase, and neuropeptides. 1110 84


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