Calcium-dependent release of somatostatin and neurotensin from rat brain in vitro

Iversen, Leslie L.; Iversen, Susan D.; Bloom, Floyd E.; Douglas, Carolyn J.; Brown, Marvin R.; Vale, Wylie

doi:10.1038/273161a0

Cited by 345 publications

(68 citation statements)

References 16 publications

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“…Somatostatin is contained in, and released from, many central and peripheral neurones and therefore has been implicated as a transmitter in the nervous system (Vale, Rivier & Brown, 1977;Iversen, Iversen, Bloom, Douglas, Brown & Vale, 1978). The most common neuronal action of somatostatin is one of inhibition with its most common cellular mechanism of action being a membrane hyperpolarization brought about by activation of inwardly rectifying potassium channels Inoue, Nakajima & Nakajima, 1988;Lewis & Clapham, 1989;Sims, Lussier & Kraicer, 1991) .…”

Section: Introductionmentioning

confidence: 99%

Somatostatin‐mediated inhibitory postsynaptic potential in sympathetically denervated guinea‐pig submucosal neurones.

Shen

Surprenant

1993

The Journal of Physiology

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SUMMARY1. Intracellular recordings were made from submucosal neurones in guinea-pig ileum. In some animals, the extrinsic (sympathetic) nerves to the submucosal plexus were severed 5-7 days previously. 4. Recovery from desensitization was rapid and followed the time course of agonist wash-out. Forskolin, phorbol esters, dithiothreitol, hydrogen peroxide, concanavalin A, or reducing temperature from 35 to 29°C did not alter the time course, degree of, or recovery from desensitization.5. The somatostatin-induced desensitization was of the homologous type; no cross-desensitization to opiate or a2-adrenoceptor agonists (which activate the same potassium conductance) occurred.6. Somatostatin desensitization did not alter the adrenergic IPSP seen in sympathetically innervated preparations but abolished the non-adrenergic IPSP recorded from normal preparations and from preparations in which the extrinsic sympathetic nerve supply had been surgically removed.7. The selective blockade of the non-adrenergic IPSP by the homologous-type somatostatin desensitization characterized in the present study provides strong support for the hypothesis that somatostatin is the neurotransmitter underlying the non-adrenergic IPSP in both normal and extrinsically denervated submucosal neurones.

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Section: Introductionmentioning

confidence: 99%

Somatostatin‐mediated inhibitory postsynaptic potential in sympathetically denervated guinea‐pig submucosal neurones.

Shen

Surprenant

1993

The Journal of Physiology

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“…In subsequent years, somatostatin was described as a neurotransmitter and neuromodulator (for review, see Reichlin, 1983). Somatostatin is synthesized in numerous neurons throughout the brain (Johansson et al, 1984) and is released in a Ca 2ϩ -dependent manner (Iversen et al, 1978). The peptide is thought to be involved in various complex functions of the CNS, such as the sensation of pain (Kuriashi et al, 1985) and the formation of memory (Matsuoka et al, 1994).…”

mentioning

confidence: 99%

Somatostatin Inhibits Excitatory Transmission at Rat Hippocampal Synapses via Presynaptic Receptors

1997

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Somatostatin is one of the major peptides in interneurons of the hippocampus. It is believed to play a role in memory formation and to reduce the susceptibility of the hippocampus to seizurelike activity. However, at the cellular level, the actions of somatostatin on hippocampal neurons are still controversial, ranging from inhibition to excitation. In the present study, we measured autaptic currents of hippocampal neurons isolated in singleneuron microcultures. Somatostatin and the analogous peptides seglitide and octreotide reduced glutamatergic, but not GABAergic, autaptic currents via pertussis toxin-sensitive G-proteins. This effect was observed whether autaptic currents were mediated by NMDA or non-NMDA glutamate receptors. Furthermore, somatostatin did not affect currents evoked by the direct application of glutamate, but reduced the frequency of spontaneously occurring excitatory autaptic currents. These results show that presynaptic somatostatin receptors of the SRIF 1 family inhibit glutamate release at hippocampal synapses. Somatostatin, seglitide, and octreotide also reduced the frequency of miniature excitatory postsynaptic currents in mass cultures without affecting their amplitudes. In addition, all three agonists inhibited voltage-activated Ca 2ϩ currents at neuronal somata, but failed to alter K ϩ currents, effects that were also abolished by pertussis toxin. Thus, presynaptic somatostatin receptors in the hippocampus selectively inhibit excitatory transmission via G-proteins of the G i /G o family and through at least two separate mechanisms, the modulation of Ca 2ϩ channels and an effect downstream of Ca 2ϩ entry. This presynaptic inhibition by somatostatin may provide a basis for its reportedly anticonvulsive action.

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“…This tridecapeptide, isolated originally in Leeman's laboratory, has the typical diversity of anatomical sites of concentration indicative of relation to many functions. These features of its behaviour are characteristic for a neurotransmitter: it is enriched in synaptosomal and microsomal subcellular fractions (Uhl & Snyder 1976); it is released from hypothalamic slices by depolarizing concentrations of external potassium in a Catt-dependent fashion (Iversen et al 1978); its brain tissue stores remain stable during superfusion; and it binds to synaptic membranes in a highly specific, saturable and reversible fashion (Kitabagi et al 1977). The immunofluorescence studies of both the Hokfelt and Snyder groups show it to be concentrated in the substantia gelatinosa of the spinal cord, trigeminal nucleus caudalis and in the ventral portions of the periaqueductal gray matter.…”

Section: Neurotensin (Nt)mentioning

confidence: 99%

“…Neurochemical studies intimating a neurotransmitter role for SaM include the following facts: it is concentrated in synaptosomal fractions and in synaptic vesicles (Berelowitz et al 1978); it is released from slices of rat hypothalamus and amygdala in a calcium-dependent fashion (Iversen et al 1978) and high potassium releases it from hypothalamic synaptosomes.…”

Section: Somatostatin (Sam)mentioning

confidence: 99%

Neuropeptides and Monoaminergic Neurotransmitters: Their Relation to Pain

Sweet

1980

J R Soc Med

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The discovery of oligopeptides, short chains of amino acids, in the normal central nervous system (CNS) has added a new and at present bewildering scope to our awareness of how the brain and spinal cord regulate their own activity. Precise localizations of these substances have followed the identification of the amino acid sequence of each peptide, the relative ease with which each is synthesized, and the development of progressively more specific antibOdies to each peptide conjugated to a carrier protein as antigen. Two powerful neuroanatomical techniques are in use: (I) Immunocytochemical methods permit light microscopy by the indirect fluorescent technique of Coons (1958),or by the peroxidase-antiperoxidase method of Sternberger (1974) and Moriarty (1973). The addition of osmic acid to the latter method increases the electron density of the reaction products and permits electron microscopy to show details of peptide relationships in the subcellular organelles. The immunoreactive staining does not, however, increase in linear fashion with increased concentration of the peptide. (2) Radioimmunoassay does yield quantitative data on concentrations of peptide in frozen specimens of CNS identified and excised under operative microscopy (Kobayashi et al. 1977). The commonest radiolabels are 3H and 1251. The British investigators Hughes and Kosterlitz of Aberdeen, the Iversens and their collaborators at the University of Cambridge, the groups of Hokfelt of Stockholm, Leeman of Boston and Snyder of Baltimore have made many of these major discoveries.One of the most clear-cut features of the new data is that nearly every one of these peptides is concentrated at such diverse sites as to connote widely varying functions for each of them. Conversely, each function has associated with it an astounding number of different peptides. To illustrate these points,

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Calcium-dependent release of somatostatin and neurotensin from rat brain in vitro

Cited by 345 publications

References 16 publications

Somatostatin‐mediated inhibitory postsynaptic potential in sympathetically denervated guinea‐pig submucosal neurones.

Somatostatin‐mediated inhibitory postsynaptic potential in sympathetically denervated guinea‐pig submucosal neurones.

Somatostatin Inhibits Excitatory Transmission at Rat Hippocampal Synapses via Presynaptic Receptors

Neuropeptides and Monoaminergic Neurotransmitters: Their Relation to Pain

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