Neurochemical features and synaptic connections of large physiologically-identified GABAergic cells in the rat frontal cortex
Section snippets
Antibodies and antisera
A monoclonal antibody raised against CCK/Gastrin (No. 28.2 MoAb) was provided by CURE/UCLA/DDC Antibody/RIA Core.[57]As a control it was preabsorbed with an excess (10−6 M) of sulphated CCK-octapeptide (Peptide Inst. Inc., Japan), resulting in no stainings in the rat frontal cortex. The bulk of CCK-like immunoreactivity in the cerebral cortex is closely similar to the sulphated CCK octapeptide.[25]Therefore, the structures stained with this antibody in the present study were considered to be
Physiological and morphological properties of large immunohistochemically-identified non-pyramidal cells
First, we have investigated the immunohistochemical, physiological and morphological characteristics of large non-pyramidal cells, and which large cells had axon collaterals with boutons apposed to somata at the light microscopic level. In the rat frontal cortex, CCK-, somatostatin- and parvalbumin-immunoreactive neurons contained large non-pyramidal cells. Therefore, following three experiments were done: (1) It was confirmed that CCK, somatostatin and parvalbumin were expressed in separate
Discussion
The major findings of the present study in the frontal cortex of young rats can be summarized as follows (Fig. 13): (1) Large non-pyramidal cells in layers II/III included CCK RS/BSNP, somatostatin RSNP and parvalbumin FS cells. (2) Some of the axon terminals of large CCK RS/BSNP cells were apposed to other somata by multiple boutons. (3) Large somatostatin cells were RSNP cells with wide or ascending axonal arbors. (4) Parvalbumin cells included chandelier cells with vertical rows of axonal
Conclusions
The somata of cortical cells are innervated by subgroups of cells containing parvalbumin or neuropeptides. The same areas of dendrites may be innervated by multiple types of GABAergic terminals from separate populations of non-pyramidal cells with distinct physiological and chemical properties. Thus in some cases cortical cells are regulated by convergent GABAergic inputs from separate sources. To further understand the physiological roles of these GABAergic cells, it is necessary to clarify
Acknowledgements
This work was supported by the Frontier Research Program, RIKEN, and Grants-in-Aid from the Japanese Ministry of Education, Science, Sports and Culture. We thank Ms Naoko Wada and Ms Satoko Kato for technical assistance. We are grateful to Dr Robert Benoit for an antiserum against somatostatin 28. Antibody No. 28.2 MoAb raised against gastrin/CCK was provided by CURE/UCLA/DDC Antibody/RIA Core.
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