The distribution of somatostatin‐like immunoreactivity in the monkey hippocampal formation

Bakst, I.; Morrison, John H.; Amaral, David G.

doi:10.1002/cne.902360402

Cited by 81 publications

(51 citation statements)

References 47 publications

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“…The presence of somatostatin-like immunoreactivity has been reported in several monkey brain regions, including prefrontal, temporal and occipital cortex, neocortex and the hippocampal formation (Bakst et al 1985;Lewis et al 1986;Campbell et al 1987;De Lima and Morrison 1989). There was a reasonably good correlation between SR1F levels in neurons and/or fibers reported by these authors and [125I]LTT-SR1F-28 labelling found in this study.…”

Section: Discussionsupporting

confidence: 76%

Somatostatin receptors in the Rhesus monkey brain: localization and pharmacological characterization

Piwko

Hoyer

1996

Naunyn-Schmiedeberg's Arch Pharmacol

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To characterize the nature and distribution of somatostatin (SRIF) receptors, radioligand binding studies and in vitro receptor autoradiography were performed in Rhesus monkey brain using either [125I]LTT-SRIF-28 ([Leu8, D-Trp22, 125I-Tyr25]SRIF-28) alone or in the presence of 3 nM seglitide (to block sst2 sites), [125I]Tyr3-octreotide or [125I]CGP 23996 (c[Asu-Lys-Asn-Phe-Trp-Lys-Thr-Tyr-Thr-Ser]) in buffer containing either 120 mM Na+ or 5 mM Mg2+. [125I]Tyr3 -octreotide labelled an apparently homogeneous population of sites in cerebral and cerebellar cortex (Bmax = 27.3 +/- 2.8 fmol/mg protein and 52.6 +/- 8.6 fmol/mg protein, PKd = 9.46 +/- 0.03 and] 9.93 +/- 0.03, respectively). The pharmacological profile of these sites correlated highly significantly with that of human recombinant sst2 receptors (r = 0.996), but not or much less with that of human recombinant sst3 and sst5 receptors (r = 0.12 and 0.45, respectively). [125I]CGP 23996 (in Na(+)-buffer) also labelled an apparently homogeneous population of sites in Rhesus monkey cerebral cortex membranes (Bmax = 3.1 +/- 0.3 fmol/mg protein, pKd = 10.57 +/- 0.08), the pharmacological profile of which was highly significantly correlated with the profiles of human recombinant sst1 and sst4 receptors (r = 0.98 and 0.96, respectively). Using receptor autoradiography, high levels of [125I]LTT-SRIF-28 and [125I]Tyr3 -octreotide recognition sites were found in basal ganglia, molecular and granular layers of the cerebellum and layers III, V and VI of entorhinal cortex. In these regions, the addition of 3 nM seglitide produced a marked decrease of [125I]LTT-SRIF-28 binding. Low levels of [125I]LTT-SRIF-28 binding were observed in subiculum, pituitary and choroid plexus. By contrast, [125I]CGP 23996 labelling in the presence of Mg2+ as well as Na+ ions was highest in pituitary and choroid plexus. However, [125I]CGP 23996 binding was diversely affected by these ionic conditions in several regions of hippocampus and cerebral cortex. Displacement of [125I]CGP 23996 (in Mg(2+)-buffer) with seglitide in the molecular layer of the cerebellum, deep layers of the entorhinal cortex, layers I, II and V of the insular cortex and frontal pole yielded complex competition curves suggesting the presence of two populations of SRIF receptors. By contrast, [125I]CGP 23996 binding (in Mg(2+)-buffer) in the choroid plexus, hilus of the dentate gyrus and stratum oriens and radiatum of the CA3 field of hippocampus was not affected by seglitide up to 10 microM, suggesting only sst1 and/or sst4 sites which have a negligible affinity for seglitide to be present in these structures. Taken together, these results suggest that [125I]CGP 23996 (in the presence of Na+) labels exclusively SRIF-2 receptors (sst1 and/or sst4), whereas in the presence of Mg2+ ions, [125I]CGP 23996 labels both SRIF-2 and SRIF-1 receptors (sst2, sst3 and sst5). The present study also demonstrates the presence and differential distribution of sst2 and sst1/sst4 receptors in the Rhesus monkey brain.

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Section: Discussionsupporting

confidence: 76%

Somatostatin receptors in the Rhesus monkey brain: localization and pharmacological characterization

Piwko

Hoyer

1996

Naunyn-Schmiedeberg's Arch Pharmacol

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“…Sloviter and Nilaver (1987) and LkrBnth et al (1990) reported a rare few SOM+ cells resembling pyramidal basket cells in the rat. A sirnilar finding has been reported by Bakst et al (1985) in the macaque monkey. Some VIP+ cells resemble pyramidal (Kiihler, 1983) and ML basket cells (Swanson ct al., 1987).…”

Section: Non-principal Cellsmentioning

confidence: 77%

Connection matrix of the hippocampal formation: I. The dentate gyrus

1995

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The hippocampal formation presents a special opportunity for realistic neural modeling since its structure, connectivity, and physiology are better understood than that of other cortical components. A review of the quantitative neuroanatomy of the rodent dentate gyrus (DG) is presented in the context of the development of a computational model of its connectivity. The DG is a three-layered folded sheet of neural tissue. This sheet is represented as a rectangle, having a surface area of 37 mm2 and a septotemporal length of 12 mm. Points, representing cell somata, are distributed in the model rectangle in a roughly uniform fashion. Synaptic connectivity is generated by assigning each presynaptic cell a spatial zone representing its axonal arbor. For each postsynaptic cell, a list of potential presynaptic cells is compiled, based on which arbor zones the given postsynaptic cell falls within. An appropriate number of presynaptic inputs are then selected at random. The principal cells of the DG, the granule cells, are represented in the model, as are non-principal cells, including basket cells, chandelier cells, mossy cells, and GABAergic peptidergic polymorphic (GPP) cells. The neurons of layer II of the entorhinal cortex are included also. The DG receives its main extrinsic input from these cells via the perforant path. The basket cells, chandelier cells, and GPP cells receive perforant path and granule cell input and exert both feedforward and feedback inhibition onto the granule cells. Mossy cells receive converging input from granule cells and send their output back primarily to distant septotemporal levels, where they contact both granule cells and non-principal cells. To permit numerical simulations, the model must be scaled down while preserving its anatomical structure. A variety of methods for doing this exist. Hippocampal allometry provides valuable clues in this regard.

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“…Thus we have reason to believe that the pattern of immunoreactivity in fact represents the distribution of parvalbumin-containing fibers and terminals. The preferred termination of PARV-immunoreactive terminals within or close to the cell layers suggests that the somatostatin-containing subgroup of nonpyramidal cells, which in the fascia dentata terminates in the outer molecular layer (Bakst et al 1985;Milner and Bacon 1989;Leranth et al J 989), does not contain PARV. This is in line with a recent report by Kosaka et al (1988) suggesting that parvalbumin and somatostatin rarely co-exist in the same nonpyramidal cell.…”

Section: P a R V-containing Cell Typesmentioning

confidence: 94%

The parvalbumin-containing nonpyramidal neurons in the rat hippocampus

1990

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The calcium-binding protein parvalbumin is considered to be involved in the control of intracellular ion homeostasis of highly active inhibitory neurons. A review of the light and electron microscopical features as well as the identified synaptic connections of these neurons is presented. Parvalbumin-containing neurons are mostly located within or in the vicinity of the granule or pyramidal cell layer. They form a subgroup of GABAergic neurons that has a target specificity for the cell body region. Their fine structural characteristics are identical to those known for hippocampal inhibitory neurons. Parvalbumin-containing neurons are involved in several inhibitory pathways: feed-back inhibition, feed-forward inhibition and disinhibition. The functional implications of our own as well as published data are discussed. Special consideration is given to the possible physiological role of parvalbumin in these neurons.

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The distribution of somatostatin‐like immunoreactivity in the monkey hippocampal formation

Cited by 81 publications

References 47 publications

Somatostatin receptors in the Rhesus monkey brain: localization and pharmacological characterization

Somatostatin receptors in the Rhesus monkey brain: localization and pharmacological characterization

Connection matrix of the hippocampal formation: I. The dentate gyrus

The parvalbumin-containing nonpyramidal neurons in the rat hippocampus

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