Regional distribution of choline acetyltransferase and acetylcholinesterase in rabbit brain

Regional distribution of choline acetyltransferase (CAT) and acetylcholinesterase (AChE) in seventeen regions of the rabbit CNS has been determined by means of the cation exchange radiometric method. A significant correlation has been found between the activities of AChE and CAT which allows computation of their potencies. A comparison between activities of the cholinergic enzymes in the human and rabbit brain has been discussed.     

Contribution to histochemical distribution of non-specific cholinesterase activity in sensory ganglia of some mammals

The activity of non-specific cholinesterase was demonstrated histochemically in satellite cells of the spinal ganglia from adult rat, cat, rabbit and baboon. The spinal ganglia of newborn rats displayed distinct intraneuronal reactivity for non-specific cholinesterase while a low reactivity was observed in satellite cells. The spinal and trigeminal ganglia of adult mice contained satellite cells with non-specific cholinesterase reactivity only sporadically. Most of reaction product for non-specific cholinesterase activity (from low to high intensity) was found in perikarya of the neurons. Spinal and trigeminal ganglia of the same mice embryo exhibited diffuse staining for non-specific cholinesterase activity remaining in the spinal ganglia of newborn mice. The trigeminal ganglia of newborn mice exhibited, however, more differentiated pattern of the positive reaction for non-specific cholinesterase like adult animals. The pattern of histochemical distribution of non-specific cholinesterase activity in trigeminal and spinal ganglia from mice of various ages corresponds with morphological differentiation and maturation undergoing in a rostrocaudal wave. Intraneuronal presence of non-specific cholinesterase activity in sensory ganglia during development and in adult animals gives a new possibilities for explanation of the functional involvement of this enzyme in the nervous system.     

Localization of acetylcholinesterase and choline acetyltransferase in the rat pituitary gland

Summary Experiments were conducted to determine the presence of two cholinergic biomarkers, acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) in the rat pituitary. A histochemical procedure for AChE was used to provide visualization of structures containing this enzyme. Radiochemical methods provided a sensitive assay for measuring ChAT activity. Nerve fibres staining for AChE activity were observed in the neurointermediate lobe, with the greatest concentrations appearing at the junction region with the pituitary stalk. Cells staining for AChE were found in the pars distalis and pars intermedia. ChAT activity correlated well with AChE distribution in pars nervosa and pars intermedia but not in pars distalis. The greatest levels of ChAT activity were in pars intermedia and the region where the stalk joins the pituitary. Significant values were also found for the pars nervosa. The presence of AChE and ChAT in pars intermedia and pars nervosa is evidence for a cholinergic innervation to these regions. In pars distalis, where other investigators have found muscarinic receptors, intense staining for AChE and absence of ChAT activity may indicate non-innervated, acetylcholine-sensitive sites.     

Changes in choline acetyltransferase activity and high-affinity choline uptake, but not in acetylcholinesterase activity and muscarinic cholinergic receptors, in rat somatosensory cortex after sciatic nerve injury

Selected cholinergic markers (choline acetyltransferase, acetylcholinesterase, muscarinic acetylcholine receptor, high-affinity choline uptake) were studied in the hindlimb representation areas of the rat somatosensory cortex and within the visual cortex 1 to 63 days after unilateral transection of the sciatic nerve. In the contralateral somatosensory cortex, peripheral deafferentation resulted in a significant reduction of choline acetyltransferase activity (by 15%) 3 days after sciatic nerve injury, and in a significant reduction of high-affinity choline uptake (by 30%) 1 day after nerve transection, in comparison to untreated control rats. Investigations in individual cortical layers revealed that the decrease of both choline acetyltransferase activity and high-affinity choline uptake sites was mainly due to reductions in cortical layer V. Acetylcholinesterase activity and [3H]quinuclidinyl benzilate binding to muscarinic acetylcholine receptors were not affected by unilateral transection of the sciatic nerve. In the ipsilateral somatosensory cortex, as well as in the visual cortex at both cortical hemispheres, no significant changes in the cholinergic parameters studied could be detected. The data indicate that peripheral deafferentation of the somatosensory cortex results in a transient change of presynaptic cholinergic parameters within the affected somatosensory area as early as 1 to 3 days after the lesion; thus, they emphasize the involvement of cholinergic mechanisms in cortical reorganizational events.     

Some properties of frog vestibular choline acetyltransferase and acetylcholinesterase

The amount and some properties of choline acetyltransferase (ChAT) and of acetylcholinesterase (AchE) were investigated in the frog vestibule. Enzyme activities were found to be of the same order of magnitude as in frog nervous tissue and various properties of vestibular ChAT (dependence on pH, chloride and Triton X-100 activation, phosphate sensitivity) and AchE (inhibition by eserine but not by Tetraisopropylpyrophosphoramide) were also similar as those of the homologous central nervous system enzymes. Although the precise localization of ChAT and AchE is not yet certain the efferent neurotransmitter in the vertebrate vestibular sensory periphery is believed to be acetylcholine and thus the enzymes responsible for its synthesis and degradation may participate in regulating inner ear function.     

Distribution of choline acetyltransferase and acetylcholinesterase in the nervous system of the dog

Choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activity were determined in 23 selected parts of the dog CNS and 4 parts of the peripheral nervous system. Maximum ChAT activity was found in the caudate nucleus and the ventral roots of the spinal cord. High activity was also present in the thalamus, the pons, the cerebral cortex, the medulla oblongata, the ventral spinal horns and the sciatic nerve. The lowest activity was measured in the cerebellum, the dorsal cord roots and the spinal ganglia. Maximum AChE activity was found in the caudate nucleus and the cerebellum. Relatively high activity was also present in the thalamus, the pons, the medulla oblongata, the grey matter of the spinal cord and the spinal ganglia. The lowest AChE activity was measured in the ventral and dorsal spinal roots.     

Developmental changes of choline acetyltransferase (ChAc) activity in chick embryo spinal and sympathetic ganglia

The ChAc activity of spinal and sympathetic ganglia was measured throughout the embryonic life of the chick. In spinal ganglia, the ChAc activity reached a first peak when the maximal proliferation of neuroblasts occurred. Then, the relative ChAc activity decreased. After the 12th day of incubation, the enzyme activity increased again and reached a second peak on the 16th day. In sympathetic ganglia, the general course of the development of ChAc activity was similar to spinal ganglia. However, higher enzymic activity was found. Furthermore, the earlier peak of ChAc activity occurred 48 hr later than the corresponding peak in spinal ganglia. The behaviour of ChAc activity in these two areas of the developing nervous system is interpreted as a function of their histogenesis.     

Radiochemical micro assays for the determination of choline acetyltransferase and acetylcholinesterase activities

1. The methods for the assay of choline acetyltransferase were based on the reaction between labelled acetyl-CoA and unlabelled choline to give labelled acetylcholine. 2. Both synthetic acetyl-CoA and acetyl-CoA formed from sodium [1-(14)C]acetate or sodium [(3)H]acetate by incubation with CoA, ATP, Mg(2+) and extract from acetone-dried pigeon liver were used. 3. [1-(14)C]Acetylcholine was isolated by extraction with ketonic sodium tetraphenylboron. 4. [(3)H]Acetylcholine was precipitated with sodium tetraphenylboron to remove a ketone-soluble contaminant in sodium [(3)H]acetate and then extracted with ketonic sodium tetraphenylboron. 5. The values of choline acetyltransferase activity obtained in the presence of sodium cyanide or EDTA and synthetic acetyl-CoA were similar to those obtained with acetyl-CoA synthesized in situ. 6. The assay of acetylcholinesterase was based on the formation of labelled acetate from labelled acetylcholine. The labelled acetylcholine could be quantitatively removed from the acetate by extraction with ketonic sodium tetraphenylboron. 7. The methods were tested with samples from central and peripheral nervous tissues and purified enzymes. 8. The blank values for choline acetyltransferase and acetylcholinesterase corresponded to the activities in 20ng. and 5ng. of brain tissue respectively.     

Activity of choline acetyltransferase and acetylcholinesterase in the goldfish optic tectum after disconnection

Activities of choline acetyltransferase (CAT) and acetylcholinesterase (AChE) were investigated in the goldfish optic tectum after disconnection of the optic afferents. Permanent disconnection was achieved by eye removal, and optic nerve crush produced a temporary disconnection until regeneration. There was a rapid loss in total activity per tectum for both enzymes under the two disconnection conditions. At longer intervals after optic nerve crush the levels of total activity for both enzymes returned toward control levels, as regeneration of the nerve proceeded. Total activity for both enzymes remained depressed after eye removal, however. Variable results were obtained in specific activity data, expressed per unit protein, although ther was a 10% loss in specific activity of CAT at early intervals after eye removal. The data are interpreted as consistent with the possibility that at least a fraction of the axons in the retinotectal pathway of goldfish are cholinergic, and parallel our previous observations showing similar rapid losses of nicotinic-cholinergic receptor activity in this system.