Molecular Forms of Acetylcholinesterase in the Developing Chick Visual System

Villafruela, Maria J.; Barat, Ana; Manrique, Esteban; Villa, Salvador; Ramı́rez, Galo

doi:10.1159/000112738

Cited by 28 publications

(12 citation statements)

References 20 publications

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“…The improved ex traction of the quail forms with the MgC me dium and earlier reports of improved extrac tion by cholate containing medium by Ramir ez and colleagues [1,33] illustrate the impor tance of the techniques used to solubilize and separate AChE forms.…”

Section: Discussionmentioning

confidence: 80%

See 1 more Smart Citation

Regulation of Acetylcholinesterase Forms in Quail and Chicken Muscle Cultures

Bulger

Randall²,

Nieberg³

et al. 1982

Dev Neurosci

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High molecular forms of acetylcholinesterase (AChE) have been difficult to obtain in primary cultures of muscle from mammals and birds. This research used pectoral muscle cultures from Japanese quail and chick embryos grown in medium containing embryo extract and horse serum to study the growth and extraction conditions necessary for study of high molecular weight 20S AChE forms found in these birds. The results confirmed the presence of a 20S AChE form in quail muscle cultures and showed that its extraction from the cells was considerably improved by using a Mg-cholate extraction buffer rather than the more commonly used NaCl-Triton X buffer. A striking finding was that removal of serum from the medium for 1–2 days caused the preferential increase in a 20S form in the quail and the resolution of one from background activity in chick muscle cultures. Removal of embryo extract had no effect on levels of the AChE forms. The results suggest that serum factors inhibit the formation of the high molecular weight, motor end plate associated form of AChE in aneural cultures of avian muscle, and that effects of factors such as neural extracts and nerves on AChE forms in cultured muscle should be examined using a defined basal media.

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Section: Discussionmentioning

confidence: 80%

“…It solubilized virtually 100% of the AChE ac tivity from homogenates of chicken muscle cultures and more than 85% of the AChE ac tivity of quail muscle culture homogenates. NaT buffer, commonly used for this purpose [1,26,27,33], was less effective in solubiliz ing AChE. …”

Section: Extraction O F Ac He From Culturesmentioning

confidence: 99%

Regulation of Acetylcholinesterase Forms in Quail and Chicken Muscle Cultures

Bulger

Randall²,

Nieberg³

et al. 1982

Dev Neurosci

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“…It has been reported that AChE and BChE occur in retina (Barat et al, 1980;Villafruela et al, 1981;Layer and Sporns, 1987;Hutchins, 1987) and in RPE (Martelly and Gautron, 1988;Salceda and Martinez, 1992;. Globular AChE forms predominate in chick retina.…”

Section: Introductionmentioning

confidence: 97%

Acetyl‐ and butyrylcholinesterase activities in the rat retina and retinal pigment epithelium

Sánchez‐Chávez

Vidal

Salceda

1995

J of Neuroscience Research

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The acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities in the neural retina and retinal pigment epithelium (RPE) of adult rats were determined. The tissues were extracted with a saline buffer to release the soluble enzymes (S1) and the pellet re-extracted with Triton X-100 to detach the membrane-bound enzymes (S2). Less than 5% of the cholinesterase activity measured in retina and almost 30% of that assayed in RPE was due to BChE. About 20% and 10% of the AChE in retina and RPE was brought into solution with a saline buffer and the rest with a detergent-containing buffer. Main AChE molecular forms of 10.5S (hydrophilic G4H), 9.5S (amphiphilic G4A) and 3.0S (amphiphilic G1A) were identified in retina by subjecting the supernatant S1 to sedimentation analysis in sucrose gradients made with Brij 96. Amphiphilic G4 and G1 AChE were found in S2. Analysis of the soluble fractions obtained from RPE in the gradients made with Brij 96 revealed 16.0S (asymmetric A12), 10.5-10.0S (globular G4H + G4A), 4.5S (G2A), and 3.0S (G1A) AChE forms in S1, whereas G4A, G2A, and G1A enzyme molecules predominated in S2. Our results show that amphiphilic tetramers and monomers of AChE are abundant in neural retina, and enzyme tetramers, dimers, and monomers in RPE. The AChE in the neural retina might be involved in cholinergic actions. The enzyme function in the retinal pigment epithelium remains to be established.

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“…The molecular complexity of acetylcholinesterase (AChE: EC 3.1.1.7) in the chick retina has been extensively studied Gomez-Barriocanal et al, 1981;Villafruela et al, 1981;Barat et al, 1983). As in many other neural structures with a cholinergic component, chick retina contains both asymmetric (A-forms) and globular (G-forms) AChE isoenzymes.…”

Section: Introductionmentioning

confidence: 99%

“…In turn, chick retinal G-forms are mainly of the detergent-soluble type (MassouliC and Bon, 1982). These molecular species of retinal AChE show distinctive patterns of embryonic and postnatal development (Villafruela et al, 1981;Barat et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Compartmentalization of acetylcholinesterase in the chick retina

Ramı́rez¹,

Barat²,

Donoso³

et al. 1989

J of Neuroscience Research

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Using selective inhibitor treatments, we have studied the distribution of asymmetric (A) and globular (G) forms of acetylcholinesterase (AChE) in the extra- and intracellular compartments of chick retina, a specialized region of chick central nervous system (CNS). Our results show that the chick retinal collagen-tailed AChE (an example of class II asymmetric molecular forms) is essentially an extracellular form of the enzyme; this is the first demonstration of the extracellular localization of asymmetric AChE in the vertebrate CNS. The active site of most of the hydrophobic, membrane-bound G4-form is also exposed to the external environment. In turn, the smaller molecular weight G-forms (G2 and G1) are localized within the cells, where they may represent intermediate components in the assembly or degradation of the more complex enzymatic molecular species. Histoenzymatic ultrastructural techniques show internal AChE in amacrine as well as in ganglion cell bodies, and external enzyme, specifically associated with synapses and axons, in the inner plexiform layer. The probable cooperation of the extracellular A12-forms and the membrane-bound G species (mainly G4) of the enzyme to the hydrolysis of acetylcholine (ACh) released into the external compartment is suggested and discussed.

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Molecular Forms of Acetylcholinesterase in the Developing Chick Visual System

Cited by 28 publications

References 20 publications

Regulation of Acetylcholinesterase Forms in Quail and Chicken Muscle Cultures

Regulation of Acetylcholinesterase Forms in Quail and Chicken Muscle Cultures

Acetyl‐ and butyrylcholinesterase activities in the rat retina and retinal pigment epithelium

Compartmentalization of acetylcholinesterase in the chick retina

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