A radiochemical method for the estimation of choline acetyltransferase

Fonnum, Frode

doi:10.1042/bj1000479

Cited by 107 publications

(33 citation statements)

References 15 publications

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“…The concentration of ChA found in the hypothalamus compares favourably with that reported by Hebb (1955) and Hebb & Silver (1956). Other recent findings employing bio-assay and radiochemical methods in parallel show also similar concentrations of ChA in the rabbit hypothalamus (Fonnum, 1966).…”

Section: Discussionsupporting

confidence: 85%

Acetylcholine and related enzymes in the neural lobe and anterior hypothalamus of the rabbit

Lederis¹,

Livingston²

1969

The Journal of Physiology

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SUMMARY1. Acetylcholine (ACh), cholinesterases and choline acetyltransferase (choline acetylase) were estimated in the neural lobe and hypothalamus of the adult male rabbit. Acetylcholine was also estimated in the neural lobes and hypothalami of some other mammals.2. Acetylcholine-like activity was measured by bio-assay using the leech dorsal muscle preparation.3. Characterization experiments indicated that about 90 % of the activity measured was due to acetylcholine.4. Mean acetylcholine content in the neural lobe of the rabbit, after extraction with perchloric acid, was 4-38 + 0-98,g/g fresh tissue, and 4-87 + 1-53 /tg/g in the hypothalamus.5. Acetylcholine was also found to be present, in comparable concentrations, in the neural lobe of man and in the neural lobes and hypothalami of ox, rat and hedgehog.6. Acetylcholinesterase, present in the neural lobe and hypothalamus of the rabbit, hydrolysed 1-74 + 0-11 It-moles of substrate/min/g and 3-78 + 0*60 It-moles substrate/min/g fresh tissue respectively.

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Section: Discussionsupporting

confidence: 85%

Acetylcholine and related enzymes in the neural lobe and anterior hypothalamus of the rabbit

Lederis¹,

Livingston²

1969

The Journal of Physiology

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“…ChAT (EC 2.3. 1.6) activity was measured according to the radiometric method of Fonnum [31], with minor modifications. 1 Oyil of homogenate (about 2 mg protein/ ml of 10 mM EDTA.…”

Section: Methodsmentioning

confidence: 99%

The Cholinergic System in Developing Cerebellum: Comparative Study of Normal, Hypothyroid and Underfed Rats

et al. 1989

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To overcome the deficiencies of previous findings, the activities of choline acetyltransferase (ChAT) and acetylcholinesterase (AchE) were studied at very short age intervals to allow a more precise definition of the shape and timing of their developmental curves in normal, hypothyroid and underfed rats. In addition, AchE expression in developing cerebellum was studied histochemically in these three neurological models. When compared with structural findings in the literature, the results provide the following information on the normal and abnormal developing cholinergic system, related or not to cerebellar neurotransmission (1) AchE activity, unlike ChAT, can be considered as a good marker of the developing cholinergic archicerebellum. (2) ChAT and AchE are transiently expressed together in functionally noncholinergic Purkinje cells. In contrast with most regions of the central nervous system, the high ratio of ChAT to AchE activities in the early stage of cerebellar development suggests an enhanced synthesis of acetylcholine (Ach). The level of ChAT activity correlates with Purkinje cell size, supporting the concept of a neurotrophic role of Ach in early maturing macroneurons. (3) The archicerebellar cholinergic network appears to be relatively well preserved from undernutrition and, to an even greater extent, from hypothyroidism, compared to other systems of neurotransmission formed later and more widely distributed throughout the cerebellum. The presynaptic compartment seems to be more affected than the postsynaptic compartment. (4) In disagreement with some data in the literature, the abnormalities induced by both abnormal thyroidal and nutritional states were found to be irreversible.

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“…A small incision was made in the sclera and the intraocular nerve branches were exposed and cut with iridectomy scissors. Within 3 days, neuromuscular endings disappeared (G. Pilar and R. Beach, unpublished observations (Fonnum, 1966). The homogenates were diluted and 5-10 #1l.…”

Section: Methodsmentioning

confidence: 99%

Normal distribution and denervation changes of neurotransmitter related enzymes in cholinergic neurones

Giacobini

Pilar

Suszkiw

et al. 1979

The Journal of Physiology

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SUMMARY1. The activities of choline acetyltransferase (CAT) and acetylcholinesterase (AChE) were assayed in adult pigeon ciliary ganglia, in the post-synaptic ciliary and choroid nerves, and in ciliary nerve iris terminals isolated from control birds and from animals from which the oculomotor nerve was previously transacted. Enzyme activity levels were also measured in the iris terminals after surgical section of the ciliary nerves. From differences in enzyme activity between control and 3-day denervated tissues, the localization of CAT and AChE in pre-and post-synaptic elements of the ganglia and at the iris neuromuscular junctions was estimated. The fate of the preganglionic nerve terminals after denervation was investigated by electron microscopic examination ofganglia after surgical section of the oculomotor nerve.2. The CAT activity in the ganglion was distributed as follows: 60 % in presynaptic elements, 31 % in cell somas, and 9 % in intraganglionic post-synaptic axons; in the iris junctions, 98 % of the activity was present in the ciliary nerve terminals. For AChE: 20 % was present in the preganglionic terminals, 69 % in ganglion cell somas and the remaining 11 % in post-ganglionic axons; at the neuromuscular iris junctions, 20 % was found in the ciliary nerve terminals and 80 % in the iris striated muscle.3. The first changes in the fine structure of the nerve terminals were observed 14 hr after surgery, and by 24 hr marked alteration of the synaptic structure were clearly recognized. No preganglionic endings were found in 3 day-old denervated ganglia.4. There was a positive correlation between CAT activity in the control iris nerve terminals and in ganglia. After denervation, when the activity of the enzyme decreased in ganglion cell somas, there was a corresponding decrease in the postsynaptic nerves. These two findings suggest that CAT slow axoplasmic transport is related to its perikarial concentration.5. There was a 60% reduction of CAT activity in the post-synaptic elements, assayed in the 10-day denervated ganglia, which was accompanied by a 30 % decrease in activity in the iris nerve terminals. Similarly, post-synaptic AChE for AChE there were smaller changes. 6. In contrast to CAT and AChE, there were no differences in ganglionic protein content, or lactate dehydrogenase (LDH), co-enzyme A (CoA) and monoamine oxidase (MAO) levels between short-term (3 days) and long-term (10 days) denervated ganglia.7. The later decrease of CAT and AChE activity in the cell somas, axons and nerve terminals after long-term preganglionic transaction suggests that the activity of these enzymes is regulated across the synapses. It is postulated that the AChE regulation is part of a general 'trophic interaction' between neurones, but that the transsynaptic modulation of CAT is specific for cholinergic cells.

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A radiochemical method for the estimation of choline acetyltransferase

Cited by 107 publications

References 15 publications

Acetylcholine and related enzymes in the neural lobe and anterior hypothalamus of the rabbit

Acetylcholine and related enzymes in the neural lobe and anterior hypothalamus of the rabbit

The Cholinergic System in Developing Cerebellum: Comparative Study of Normal, Hypothyroid and Underfed Rats

Normal distribution and denervation changes of neurotransmitter related enzymes in cholinergic neurones

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