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EXPRESSION: positive
ANIMAL: rat
PROTOCOL: immunohistochemistry
Page location: p57, top
"Similar to O-LM [oriens--lacunosum-moleculare] cells, HIPP [hilar perforant path-associated] cells express SOM [somatostatin] (Katona et al.,
1999a)."
"While somatostatin-labeled cell bodies are confined primarily to the hilus in the dentate gyrus, their terminals fields are most prominent in the outer molecular layer where the perforant path fibers terminate (Bakst et al., 1986; Katona et al., 1999). Thus many of the somatostatin neurons in the hilus are considered to be HIPP [hilar perforant path-associated] cells, based on the location of their cell bodies and axon terminals. The dendrites of somatostatin neurons extend for considerable distances across the hilus but generally remain within the region (Fig. 5B)."
"Some well characterized interneurons are, however, covered densely by dendritic spines. These are the hippocampal O-LM [oriens-lacunosum moleculare] and the dentate
gyrus hilar perforant path-associated (HIPP) cells. Both cell types contain the neuropeptide somatostatin; and their dendrites, with prominent spines, can be visualized by immunostaining against mGluR[metabotropic glutamate receptor]1, substance P receptors, or in some cases calretinin (Freund and Buzsaki, 1996)."
"At least some of these HIPP [hilar perforant path-associated] cells
appear to correspond to the somatostatin/GABA [gamma aminobutyric acid]
cells that give rise to the somatostatin innervation
of the outer portion of the molecular layer. Antibodies directed against the peptide somatostatin
have revealed that neurons such as the
HIPP [hilar perforant path-associated] cells scattered throughout the polymorphic
layer are immunoreactive for this peptide, and account
for approximately 16% of the GABA[gamma aminobutyric acid]ergic
cells in the dentate gyrus (Morrison et al., 1982;
Bakst et al., 1986; Freund and Buzsaki, 1996;
Sik et al., 1997; Boyett and Buckmaster, 2001)."
"While somatostatin-labeled cell bodies are confined primarily to the hilus in the dentate gyrus, their terminals fields are most prominent in the outer molecular layer where the perforant path fibers terminate (Bakst et al., 1986; Katona et al., 1999). Thus many of the somatostatin neurons in the hilus are considered to be HIPP [hilar perforant path-associated] cells, based on the location of their cell bodies and axon terminals. The dendrites of somatostatin neurons extend for considerable distances across the hilus but generally remain within the region (Fig. 5B)."
"Some well characterized interneurons are, however, covered densely by dendritic spines. These are the hippocampal O-LM [oriens-lacunosum moleculare] and the dentate
gyrus hilar perforant path-associated (HIPP) cells. Both cell types contain the neuropeptide somatostatin; and their dendrites, with prominent spines, can be visualized by immunostaining against mGluR[metabotropic glutamate receptor]1, substance P receptors, or in some cases calretinin (Freund and Buzsaki, 1996)."
EXPRESSION: positive
ANIMAL: mouse
PROTOCOL: immunohistochemistry
Page location: p798, left top
Linking PMID: 7472426 Linking Quote: Citation included in evidentiary quote. Linking Page Location: p798, left top
"According to the characteristic soma location and the distribution of axonal and dendritic arbors, the majority of SOM [somatostatin]-containing GABA[gamma-amino-butyric acid]ergic neurons are considered to be dendritic inhibitory cells of the hippocampus. The dendritic inhibitory cells correspond with previously reported oriens/alveus interneurons with lacunosum moleculare axon arborization (O-LM [oriens-lacunosum moleculare] cells; Sik et al., 1995) and hilar perforant path-associated neurons (HIPP cells; Han et al., 1993)."
"Although the neurochemical marker content of these intracellularly labelled neurons is largely unknown, in one case a HIPP [hilar perforant pathway-associated] cell was shown to contain neuropeptide Y (NPY). [Fruend and Buszaki 1996, Sik 1995] Since NPY and somatostatin co-localize in many hilar interneurons, [Kohler 1987] it indicates that HIPP cells express somatostatin as well."
"Dentate gyrus. Three somatostatin-immunoreactive neurons were partially reconstructed in the dentate gyrus, all of them showed typical morphological characteristics of HIPP [hilar perforant path-associated] cells [Amaral 1978, Buckamster 1995, Han 1993, Sik 1997] (Fig. 3)."
"The hilar region neurons with outer molecular layer projections were
strikingly similar to the HIPP [hilar interneurons with perforant-path associated projection] cells described by Han et al. (1993)
in vitro and Buckmaster and Schwartzkroin (1995a) in vivo. Axon
terminals in the outer molecular layer are believed to derive from
somatostatin/neuropeptide Y (NPY)-positive neurons in the hilus
(Bakst et al., 1985; Kohler et al., 1986; Sloviter and Nilaver, 1987;
Deller and Leranth, 1990; Milner and Veznedaroglu, 1992). Like our
filled neuron, NPY-positive boutons have been observed to establish
symmetrical synapses on the dendritic shafts and spines of presumed
granule cells (Deller and Leranth, 1990; Milner and Veznedaroglu,
1992)."
"According to the characteristic soma location and axonal and
dendritic distribution, hilar SOM [somatostatin]-positive cells are likely to be
identical to HIPP [hilar perforant path-associated] cells of the morphological classification scheme
(Section III.3.1.a). The correlation of morphology and neurochemical
character for this cell type is perhaps the most straightforward
of all such attempts; thus, "SOM [somatostatin] cells" and "HIPP cells"
in the dentate gyrus can be considered as synonymous."
"The correspondence between NPY[neuropeptide Y]-containing neurons and
morphologically identified cell types is quite complex. SOM [somatostatin]-positive
hilar cells with hilar dendritic arbors project to the outer
molecular layer and thus most likely correspond to HIPP [hilar perforant path-associated] cells. Direct evidence for the prediction that hilar NPY cells also correspond
to HIPP cells has been recently provided by the immunocytochemical
demonstration of NPY in an intracellularly
filled HIPP cell (Fig. 21; Sik et al., submitted)."
EXPRESSION: positive (inference)
ANIMAL: rat
PROTOCOL: immunohistochemistry
Page location: p775, right mid
"In these experiments, all the cells of the hippocampus immunoreactive for somatostatin were strongly immunoreactive for mGluR[metabotropic glutamate receptor]lalpha, and likewise the cells immunoreactive for mGluRla were also immunoreactive for somatostatin (Figures 2A and 2B)."
Interpretation notes: Glutamatergic and GABAergic mGluR1a+ types in DG Smo_Smi_SG_H are probably SOM+
"However, since HIPP cells probably correspond to somatostatin/neuropeptide Y-immunopositive neurons (Han et al., 1993), it is noteworthy that GABA/somatostatin-immunoreactive neurons gave a weaker GABA immunoreaction than somatostatin-negative, GABA-immunopositive cells (Somogyi et al., 1984). Therefore, it is possible that the normally lower GABA level in the HIPP cell contributed to the lack of GABA immunoreactivity in the slice preparation. In perfusion-fixed material of normal rat dentate gyrus almost all boutons forming type 2 synapses in the outer molecular layer, where the HIPP cell terminates, were GABA-immunopositive (K. Halasy and P. Somogyi, unpublished result). Considering these indirect lines of evidence together with the technical difficulties of immunoreaction in slice tissue, it seems probable that the HIPP cell is a GABA- and somatostatin-containing neuron."