Neurotoxic esterase in peripheral nerve: Assay, inhibition, and rate of resynthesis

Caroldi, Stefano; Lotti, Marcello

doi:10.1016/0041-008x(82)90151-x

Cited by 61 publications

(12 citation statements)

References 11 publications

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“…NTE was measured in the brain according to Johnson (197" and in the peripheral nerve according to Caroldi and Lotti (1982)z modified by Muretto et al (1989). NTE activities of control hens wet always within the range of historical values from our laboratory: 2.0-2: in brain, 0.5-0.7 in the spinal cord and 0.1 -0.15 in the peripheral nen (gmol/min/g wet wt of tissue).…”

Section: Methodsmentioning

confidence: 99%

Phenylmethanesulfonyl fluoride elicits and intensifies the clinical expression of neuropathic insults

et al. 1992

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It has been recently reported that phenylmethanesulfonyl fluoride (PMSF) when given to hens after a neuropathic organophosphate (OP) promotes organophosphate-induced delayed polyneuropathy (OPIDP). Chicks are resistant to OPIDP despite high inhibition/aging of neuropathy target esterase (NTE), the putative target of OPIDP initiation. However, when PMSF (300 mg/kg s.c.) is given to chicks after di-butyl 2,2-dichlorovinyl phosphate (DBDCVP, 1 or 5 mg/kg s.c.), OPIDP is promoted. Inhibition/aging of at least 30% of NTE was thought to be an essential prerequisite for promotion to be elicited in adult hens. However, we observed in hens that when NTE is maximally affected (greater than 90%) by phenyl N-methyl N-benzyl carbamate (40 mg/kg i.v.), a non-ageable inhibitor of NTE, and then PMSF is given (120 mg/kg/day s.c. x 3 days) clinical signs of neuropathy become evident. Methamidophos (50 mg/kg p.o. to hens), which produces in vivo a reactivatable form of inhibited NTE, was shown either to protect from or promote OPIDP caused by DBDCVP (0.45 mg/kg s.c.), depending on the sequence of dosing. Because very high doses of methamidophos cause OPIDP, we considered this effect to be a "self-promoted" OPIDP. We concluded that NTE inhibitors might have different intrinsic activities for producing OPIDP once NTE is affected. Aging might differentiate highly neuropathic OPs, like DBDCVP, from less neuropathic OPs, like methamidophos, or from the least neuropathic carbamates, which require promotion in order for neuropathy to be expressed.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Methodsmentioning

confidence: 99%

Phenylmethanesulfonyl fluoride elicits and intensifies the clinical expression of neuropathic insults

et al. 1992

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“…In the hen brain, it is mainly present in particulate form (P-NTE) bound to membranes of the microsomal fraction (Richardson et al, 1979). NTE in the sciatic nerve of the hen has been the subject of a number of publications (Caroldi and Lotti, 1982;Carrington and Abou-Donia, 1984;Bard et al, 1988). It has been reported that 4040% of NTE activity in the sciatic nerve of the hen is located in soluble form (S-NTE), and the rest is present as P-NTE (Vilanova et al, 1990).…”

mentioning

confidence: 99%

Soluble and Particulate Organophosphorus Neuropathy Target Esterase in Brain and Sciatic Nerve of the Hen, Cat, Rat, and Chick

Tormo

Gimeno

Sogorb

et al. 1993

Journal of Neurochemistry

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Considerable evidence exists suggesting that the so-called neuropathy target esterase (NTE) is involved in the mechanisms responsible for organophosphorus-induced delayed polyneuropathy (OPIDP). Earlier studies in the adult hen, the habitually employed experimental model in OPIDP, have shown that most NTE activity in the brain is centered in particulate fractions, whereas approximately 50% of this activity in the sciatic nerve is encountered in soluble form, with the rest being particulate NTE. In the present work, we have studied the particulate and soluble fractional distribution of paraoxon-resistant phenylvalerate esterase activity (B activity), paraoxon- and mipafox-resistant phenylvalerate esterase activity (C activity), and NTE activity (B-C) according to ultracentrifugation criteria (100,000 g for 1 h). To this effect, two sensitive (adult hen and cat) and two scarcely sensitive (rat and chick) models were used. In all four experimental models, the distribution pattern was qualitatively similar: B activity and total NTE were much greater in brain (900-2,300 nmol/min/g of tissue) than in sciatic nerve (50-100 nmol/min/g of tissue). The proportion of soluble NTE in brain was very low (< 2%), whereas its presence in sciatic nerve was substantial (30-50%). The NTE/B ratio in brain was high for the particulate fraction (> 60%) and low in the soluble fraction (7-30%); in sciatic nerve the ratio was about 50% in both fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Studies of NTE in the sciatic nerve have centered on the development of appropriate methods for NTE assay (Caroldi and Lotti, 1982;Baml et al, 1988) and on the study of NTE proximodistal distribution (Car-rington and Abou-Donia, 1984; Baml et al, 1988). In turn, sciatic nerve NTE activity has been determined in some toxicological studies (Lotti et al, 1987; Pellin et al, 1988; Johnson et al, 1989).…”

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confidence: 99%

Soluble and Participate Forms of the Organophosphorus Neuropathy Target Esterase in Hen Sciatic Nerve

Vilanova

Barril

Carrera

et al. 1990

Journal of Neurochemistry

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Neuropathy target esterase (NTE) is the suggested "target" molecule involved in the initiation of organophosphorus-induced delayed polyneuropathy. Sciatic nerve NTE was separated into particulate (P-NTE) and soluble (S-NTE) fractions by ultracentrifugation at 100,000 g for 1 h in 0.32 M sucrose and compared with the corresponding brain extract. Total sciatic NTE activity was 80-100 nmol/min/g tissue from which 50-60% was recovered in the soluble supernatant fraction and the remaining 40-50% in the pellet fraction. About 90% of brain tissue activity (approximately 1,800 nmol/min/g tissue) was recovered as P-NTE. A similar distribution was obtained when more drastic centrifugation without sucrose was performed. P-NTE and S-NTE were distributed with the membrane and cytosolic markers assayed, respectively, glucose-6-phosphatase, Na+,K(+)-ATPase, 5'-nucleotidase, phospholipids, and lactate dehydrogenase. When the pH during the centrifugation was increased from 6.4 to 11, recovered P-NTE activity decreased from 1,750 to 118 nmol/min/g tissue for brain and from 31 to 12 nmol/min/g for sciatic nerve. However, S-NTE activity and total nonfractionated control activity were only slightly affected by the same pH treatment. The distribution pattern encountered may be better understood as representing two different proteins than an equilibrium between soluble and membrane-bound portions of a single protein, with P-NTE activity depending on a membrane factor from which it is separated through fractionation at high pH.(ABSTRACT TRUNCATED AT 250 WORDS)

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Neurotoxic esterase in peripheral nerve: Assay, inhibition, and rate of resynthesis

Cited by 61 publications

References 11 publications

Phenylmethanesulfonyl fluoride elicits and intensifies the clinical expression of neuropathic insults

Phenylmethanesulfonyl fluoride elicits and intensifies the clinical expression of neuropathic insults

Soluble and Particulate Organophosphorus Neuropathy Target Esterase in Brain and Sciatic Nerve of the Hen, Cat, Rat, and Chick

Soluble and Participate Forms of the Organophosphorus Neuropathy Target Esterase in Hen Sciatic Nerve

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