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Whittaker VP. Some currently neglected aspects of cholinergic function. J Mol Neurosci 2010; 40:7-11. [PMID: 19787460 PMCID: PMC2807944 DOI: 10.1007/s12031-009-9247-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 07/20/2009] [Indexed: 12/01/2022]
Abstract
At the request of the organizers of the XIII International Symposium on Cholinergic Mechanisms, I have selected for review three topics not well represented at the meeting: the synthesis, storage, and release of acetylcholine at cholinergic nerve endings; cholinergic-specific antigens; and neuropeptides as cholinergic co-transmitters. The first topic is illustrated by work with two model systems, the electromotor nerve terminals of the electric ray and the myenteric plexus of the guinea-pig ileum, the second by work with Chol-1, a group of cholinergic-specific gangliosides sialylated on their N-acetylgalactosamine residues, and the third by vasoactive intestinal polypeptide which is a co-transmitter at 70% of cholinergic nerve endings in brain and is also present in both of the model cholinergic systems.
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2
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Abstract
Like non-peptidergic transmitters, neuropeptides and their receptors display a wide distribution in specific cell types of the nervous system. The peptides are synthesized, typically as part of a larger precursor molecule, on the rough endoplasmic reticulum in the cell body. In the trans-Golgi network, they are sorted to the regulated secretory pathway, packaged into so-called large dense-core vesicles, and concentrated. Large dense-core vesicles are preferentially located at sites distant from active zones of synapses. Exocytosis may occur not only at synaptic specializations in axonal terminals but frequently also at nonsynaptic release sites throughout the neuron. Large dense-core vesicles are distinguished from small, clear synaptic vesicles, which contain "classical' transmitters, by their morphological appearance and, partially, their biochemical composition, the mode of stimulation required for release, the type of calcium channels involved in the exocytotic process, and the time course of recovery after stimulation. The frequently observed "diffuse' release of neuropeptides and their occurrence also in areas distant to release sites is paralleled by the existence of pronounced peptide-peptide receptor mismatches found at the light microscopic and ultrastructural level. Coexistence of neuropeptides with other peptidergic and non-peptidergic substances within the same neuron or even within the same vesicle has been established for numerous neuronal systems. In addition to exerting excitatory and inhibitory transmitter-like effects and modulating the release of other neuroactive substances in the nervous system, several neuropeptides are involved in the regulation of neuronal development.
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Affiliation(s)
- G K Zupanc
- Max-Planck-Institut für Entwicklungsbiologie, Abteilung Physikalische Biologie, Tübingen, Germany.
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3
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Abstract
Cholinergic nerve terminals utilize glycoconjugates in several ways, as surface markers and as structural components of the synaptic vesicles present within them. The surface markers have been discovered immunochemically: antibodies raised against them are able specifically to sensitize the cholinergic subpopulation of mammalian brain synaptosomes to complement-mediated lysis. One such group of antigens (Chol-1) have been identified as a novel series of minor gangliosides having in common a sialylated N-acetylgalactosamine residue. These gangliosides may constitute the major gangliosides at cholinergic terminals. A second surface antigen (Chol-2) is thought to be a protein with an epitope in common with a Torpedo electric organ ganglioside. Cholinergic synaptic vesicles are rich in a proteoglycan which appears to assist in the sequestration of acetylcholine within the vesicle and to stabilize the vesicle membrane during cycles of exocytosis and recovery. It may be the cholinergic equivalent of the chromogranins.
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Affiliation(s)
- V P Whittaker
- Max-Planck-Institut für Biophysikalische Chemie, Göttingen, FR Germany
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Li ZS, Young HM, Furness JB. Do vasoactive intestinal peptide (VIP)- and nitric oxide synthase-immunoreactive terminals synapse exclusively with VIP cell bodies in the submucous plexus of the guinea-pig ileum? Cell Tissue Res 1995; 281:485-91. [PMID: 7553768 DOI: 10.1007/bf00417865] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In the submucous plexus of the guinea-pig ileum, previous light-microscopic studies have revealed that vasoactive intestinal peptide (VIP)-immunoreactive and nitric oxide synthase (NOS)-immunoreactive terminals are found predominantly in association with VIP-immunoreactive nerve cell bodies. In this study, double-label immunohistochemistry at the light-microscopic level demonstrated co-localization of NOS-immunoreactivity and VIP-immunoreactivity in axon terminals in submucous ganglia. About 90% of nerve fibres with NOS-immunoreactivity or VIP-immunoreactivity were immunoreactive for both antigens; only about 10% of labelled varicosities contained only NOS-immunoreactivity or VIP-immunoreactivity. The VIP/NOS varicosities were more often seen in the central parts of the ganglia, close to the VIP-immunoreactive cell bodies. Ultrastructural immunocytochemistry with antibodies to VIP was used to determine if NOS/VIP terminals synapse exclusively with VIP-immunoreactive nerve cell bodies. We examined the targets of VIP-immunoreactive boutons in two submucous ganglia from different animals. Serial ultrathin sections were taken through the ganglia after they had been processed for VIP immunocytochemistry. For each cell body, the number of VIP inputs (synapses and close contacts) was determined. The number of VIP-immunoreactive synapses received by the cell bodies of submucous neurons varied from 0-4 and the number of VIP-immunoreactive close contacts varied from 3-10. There was no significant difference between VIP-immunoreactive nerve cell bodies and non-VIP nerve cell bodies in the number of VIP-immunoreactive synapses and close contacts they received. Thus, the implication from light microscopy that NOS/VIP terminals end predominantly on VIP nerve cells was not vindicated by electron microscopy.
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Affiliation(s)
- Z S Li
- Department of Anatomy and Cell Biology, University of Melbourne, Parkville, Victoria, Australia
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Llona I, Annaert WG, Jacob W, De Potter WP. Co-storage in large 'dense-core' vesicles of dopamine and cholecystokinin in rat striatum. Neurochem Int 1994; 25:573-81. [PMID: 7894334 DOI: 10.1016/0197-0186(94)90156-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The subcellular localization of cholecystokinin in the striatum--an area where a high density of cholecystokinin containing terminals has been demonstrated--was studied using biochemical techniques. Cholecystokinin containing vesicles were partially purified using iso-osmotic Ficoll gradients. As judged from their size and their buoyant density in isopycnic gradients, cholecystokinin containing vesicles represent large 'dense-core' vesicles. Negative staining and subsequent immunolabelling for synaptophysin at the electron microscopical level, showed labelled vesicles of 50-70 nm. binding of dihydrotetrabenazine was detected in the cholecystokinin containing fractions. The results suggest that dopamine is co-stored with cholecystokinin in large dense vesicles in rat striatum.
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Affiliation(s)
- I Llona
- Department of Medicine, University of Antwerp (UIA), Belgium
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Schmidle T, Weiler R, Desnos C, Scherman D, Fischer-Colbrie R, Floor E, Winkler H. Synaptin/synaptophysin, p65 and SV2: their presence in adrenal chromaffin granules and sympathetic large dense core vesicles. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1060:251-6. [PMID: 1751512 DOI: 10.1016/s0005-2728(05)80314-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The subcellular distribution of three proteins of synaptic vesicles (synaptin/synaptophysin, p65 and SV2) was determined in bovine adrenal medulla and sympathetic nerve axons. In adrenals most p65 and SV2 is confined to chromaffin granules. Part of synaptin/synaptophysin is apparently also present in these organelles, but a considerable portion is found in a light vesicle which does not contain significant concentrations of typical markers of chromaffin granules (cytochrome b-561, dopamine beta-hydroxylase or the amine carrier). An analogous finding was obtained for sympathetic axons. The large dense core vesicles contain most p65 and also SV2 but only a smaller portion of synaptin/synaptophysin. A lighter vesicle containing this latter antigen and some SV2 has also been found. These results establish that in adrenal medulla and sympathetic axons three typical antigens of synaptic vesicles are not restricted to light vesicles. Apparently, a varying part of these antigens is found in chromaffin granules and large dense core vesicles. On the other hand, the light vesicles do not contain significant concentrations of functional antigens of chromaffin granules. Thus, the biogenesis of small presynaptic vesicles which contain all three antigens as well as functional components like the amine carrier is likely to involve considerable membrane sorting.
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Affiliation(s)
- T Schmidle
- Department of Pharmacology, University of Innsbruck, Austria
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Morin PJ, Liu NG, Johnson RJ, Leeman SE, Fine RE. Isolation and characterization of rapid transport vesicle subtypes from rabbit optic nerve. J Neurochem 1991; 56:415-27. [PMID: 1824859 DOI: 10.1111/j.1471-4159.1991.tb08167.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Subcellular fractionation of rabbit optic nerve resolves three populations of membranes that are rapidly labelled in the axon. The lightest membranes are greater than 200 nm and are relatively immobile. The intermediate density membranes consist of 84 nm vesicles which disappear from the nerve with kinetics identical to those of the rapid component. A third population of membranes, displaying a distinct protein profile, is present in the most dense region of the gradient. Immunological characterization of these membranes suggests the following. (1) The lightest peak contains rapidly transported glucose transporter and most of the total glucose transporters present in the nerve; this peak is therefore enriched in axolemma. (2) The intermediate peak contains rapidly transported glucose transporters and synaptophysin, an integral synaptic vesicle protein, and about half of the total synaptophysin; this peak therefore contains transport vesicles bound for both the axolemma and the nerve terminal, and these subpopulations can be separated by immunoadsorption with specific antibodies against the aforementioned proteins. (3) The heaviest peak contains rapidly transported synaptophysin and tachykinin neuromodulators and about half of the total synaptophysin, and 80% of the total tachykinins present in the nerve; this peak appears to represent a class of synaptic vesicle precursor bound for the nerve terminal exclusively. (4) Synaptophysin is present in the membranes of vesicles carrying tachykinins. (5) Both the intermediate and the heaviest peaks are enriched in kinesin heavy chain, suggesting that both vesicle classes may be transported by the same mechanism.
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Affiliation(s)
- P J Morin
- Department of Biochemistry, Boston University School of Medicine, MA 02118
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Fox GQ, Kötting D, Dowe GH. A morphometric analysis of isolated Torpedo electric organ synaptic vesicles following stimulation. Brain Res 1990; 525:59-70. [PMID: 2245326 DOI: 10.1016/0006-8993(90)91320-g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The electric organ of Torpedo has been stimulated with 1800 pulses at 0.1 Hz to produce biochemical and morphological heterogeneity of its synaptic vesicle population. This was verified by biochemical and morphometric analyses of the synaptic vesicle population isolated by sucrose density gradient zonal separation following stimulation. Biochemical or metabolic heterogeneity was verified using 2 established criteria: the appearance of a second peak of acetylcholine (ACh) in denser fractions of the zonal gradient and a corresponding overlapping peak of incorporated radiolabelled ACh. Morphologic heterogeneity was deduced by the presence in this second peak of a subclass of synaptic vesicles having a mean diameter of 68 nm i.e., a diameter 20-25% smaller than the 90 nm subclass that represents the most prominent subclass of the intact terminal population. Despite having satisfied these 3 criteria, functionally relevant heterogeneity cannot be assumed. One reason is due to our failure to recover the 90 nm subclass of vesicle which provides the physical basis to explain the 2 ACh peaks along the gradient. Because of this, the point is raised whether the stimulation-induced ACh peak is not merely an artifact due to inadequate sampling. On the other hand, radioactive labelling of the ACh pool provides a more convincing demonstration of the existence of 2 metabolically different subclasses. We conclude that morphological heterogeneity of the ACh vesicle population has never been established and that metabolic heterogeneity, as it has been studied to date, pertains to a single-sized subclass population of vesicles measuring 68 nm in diameter.
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Affiliation(s)
- G Q Fox
- Max-Planck-Institut für biophysikalische Chemie, Göttingen, F.R.G
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Whittaker VP. Cholinergic synaptic vesicles are metabolically and biophysically heterogeneous even in resting terminals. Brain Res 1990; 511:113-21. [PMID: 2331609 DOI: 10.1016/0006-8993(90)90230-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The metabolic heterogeneity of synaptic vesicles in the cholinergic nerve terminals of the electromotor neurons of Torpedo marmorata has been studied in resting tissue by evaluating the molecular acetylcholine content (MAC) of synaptic vesicles after extraction from frozen and crushed tissue and high-resolution centrifugal density gradient separation in a zonal rotor. Although vesicular acetylcholine was distributed in the gradient as a single, more or less symmetrical peak, 3 subpopulations of synaptic vesicles could be identified: a small, relatively light subpopulation of low MAC on the ascending limb of the acetylcholine peak, designated V0, a main population of fully charged vesicles designated V1, and a small, denser subpopulation also of low MAC on the descending limb of the acetylcholine peak, designated V2. The mean proportions and MACs of the 3 pools were: V0, 13%, 58,000; V1, 53%, 246,000; V2, 34%, 79,000. When tritiated acetate was perfused through excised blocks of electric organ for 1-2 h before vesicle isolation, the specific radioactivity of the acetylcholine in the V0 and V2 pools was 10-30 times higher than in the V1 pool. This suggests that both the V0 and V2 pools are not generated by the isolation procedure but are present in the intact endings and are functionally active. On the basis of their density and uptake of newly synthesized acetylcholine, the V0 and V2 pools were identified with the previously described VP0 pool of axonal vesicles and the VP2 pool of recycling vesicles in stimulated nerve terminals respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- V P Whittaker
- Arbeitsgruppe Neurochemie, Max-Planck-Institut für Biophysikalische Chemie, Göttingen, F.R.G
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Whittaker VP. The cell and molecular biology of the cholinergic synapse: twenty years of progress. PROGRESS IN BRAIN RESEARCH 1990; 84:419-36. [PMID: 2176303 DOI: 10.1016/s0079-6123(08)60926-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- V P Whittaker
- Arbeitsgruppe Neurochemie, Max-Planck-Institut für biophysikalische Chemie, Göttingen, F.R.G
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Shaw C, Whittaker VP, Agoston DV. Characterization of gastrin-releasing peptide immunoreactivity in distinct storage particles in guinea pig myenteric and Torpedo electromotor neurones. Peptides 1990; 11:69-74. [PMID: 2160654 DOI: 10.1016/0196-9781(90)90112-i] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Using high resolution centrifugal density-gradient separation of cytoplasmic extracts of guinea pig myenteric plexus and Torpedo electric tissue, we have succeeded in isolating fractions of storage particles rich in gastrin-releasing peptide (GRP). In extracts of myenteric plexus and gradients derived therefrom, the 10-amino acid GRP peptide (GRP-10) was the sole form present; this was bimodally distributed in the gradients, one peak copurifying with Golgi membranes and apparently consisting of immature storage particles, the other with other synaptophysin-rich neuropeptide-containing particles. In extracts of electric organ, a tissue rich in cholinergic electromotor nerve terminals, and gradients derived therefrom, GRP-like immunoreactivity behaved in gel permeation and reversed phase high performance liquid chromatography like the 27-amino acid peptide (GRP-27). About half of the immunoreactivity sedimented in the centrifugal gradient to a region rich in particles containing vasoactive intestinal polypeptide-like immunoreactivity; the remainder was recovered in a very dense region of the gradient containing larger membrane fragments, including synaptosomes. The electromotor nerves and cell bodies also contained GRP-27-like immunoreactivity in relatively high concentration as did the Torpedo gut. It is concluded that this GRP-like peptide is packaged in dense storage particles in the electromotor neurones.
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Affiliation(s)
- C Shaw
- Department of Medicine, Queen's University of Belfast, U.K
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Thureson-Klein AK, Klein RL. Exocytosis from neuronal large dense-cored vesicles. INTERNATIONAL REVIEW OF CYTOLOGY 1990; 121:67-126. [PMID: 1972143 DOI: 10.1016/s0074-7696(08)60659-2] [Citation(s) in RCA: 166] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A K Thureson-Klein
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson 39216
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Agoston DV, Fahrenkrug J, Mikkelsen JD, Whittaker VP. A peptide with N-terminal histidine and C-terminal isoleucine amide (PHI) and vasoactive intestinal peptide (VIP) are copackaged in myenteric neurones of the guinea pig ileum. Peptides 1989; 10:571-3. [PMID: 2780416 DOI: 10.1016/0196-9781(89)90144-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
When cytoplasmic extracts of the myenteric plexus of guinea pig ileum are submitted to centrifugal density gradient separation in a zonal rotor, conditions which separate storage particles containing substance P, somatostatin and VIP from each other, PHI copurifies with VIP. The two immunoreactivities cannot be separated by particle exclusion chromatography, which depends on size rather than density. It is concluded that the posttranslational cleavage of the propeptide or precursor to PHI and VIP occurs after packaging into these storage particles.
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Affiliation(s)
- D V Agoston
- Arbeitsgruppe Neurochemie, Max-Planck-Institut für Biophysikalische Chemie, Göttingen, FR Germany
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Whittaker VP. The historical significance of work with electric organs for the study of cholinergic transmission. Neurochem Int 1989; 14:275-87. [DOI: 10.1016/0197-0186(89)90053-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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