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Subpopulations of GABA neurons containing somatostatin, neuropeptide Y, and parvalbumin in the dorsomedial cortex of the lizard Psammodromus algirus
Author(s) -
Dávila Josée Carlos,
Megías Manuel,
de la Calle Adelaida,
Guirado Salvador
Publication year - 1993
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903360202
Subject(s) - parvalbumin , biology , somatostatin , neuropeptide , neuroscience , immunocytochemistry , hippocampus , neuropeptide y receptor , hippocampal formation , endocrinology , receptor , biochemistry
Different subpopulations of GABA neurons containing the neuropeptides somatostatin and neuropeptide Y, and the calcium binding protein parvalbumin were studied by immunocytochemistry using light and electron microscopy in the dorsomedial cortex of the lizard Psammodromus algirus to investigate the connectivity of different subsets of GABA neurons in the lizard dorsomedial cortical circuitry and to compare cortical regions of reptiles and mammals. GABA neurons were classified into different subsets by using the peroxidase anti‐peroxidase immunohistochemical method on adjacent Araldite‐embedded semithin sections. GABA neurons in the dorsomedial cortex fall into three major subsets: (1) neurons with somatostatin (and neuropeptide Y), which accounted for about 44% of the GABA population; (2) neurons with parvalbumin, which accounted for about 13% of the GABA neurons; and (3) neurons without parvalbumin or neuropeptides, which represented 40% of all GABA cells. This division of GABA neurons in non‐overlapping subpopulations of neuropeptide‐ and parvalbumin‐containing cells is similar to that found in the mammalian hippocampal formation. On the basis of the nerve terminal fields, somatostatin‐ and parvalbumin‐immunoreactive neuronal populations appear to be functionally different, acting on different portions of the projection neurons. Parvalbumin‐immunoreactive neurons inhibit the pyramidal neurons at the cell body level, whereas somatostatin‐immunoreactive neurons inhibit them on distal dendrites. The results of the present study add more similarities between the lizard dorsomedial cortex and parts of the mammalian hippocampus. © 1993 Wiley‐Liss, Inc.