Distribution of GABAA receptor alpha 1 subunit-like immunoreactivity in comparison with that of enkephalin and substance P in the rat forebrain.
The gamma-aminobutyric acid-A receptor consists of several subunits. In this immunohistochemical study we investigated the regional distribution of the alpha 1 subunit with an antibody directed against a specific amino acid sequence (1-9) of the (1-9) of the alpha 1 subunit. We compared the distribution pattern of the alpha 1 subunit-like immunoreactivity with that of substance P- and enkephalin-like immunoreactivities in adjacent sections of the rat forebrain. alpha 1 subunit-like immunoreactivity appeared in the form of varicosities and fibers. A band-like terminal staining pattern (woolly fibers) that has been shown by others for substance P- and enkephalin-like immunoreactivity is also observed for alpha 1 subunit-like immunoreactivity. In contrast to substance P and enkephalin, numerous alpha 1 subunit-like immunoreactive perikarya were found. The highest density of alpha 1 subunit-like immunoreactive fibers and perikarya was found in the pallidal areas and the substantia nigra pars reticulata whereas the nucleus accumbens and the caudate putamen displayed a low density. alpha 1 subunit-like immunoreactive neurons resembled typical pallidal neurons. Some of these neurons were pericellularly stained with enkephalin-like immunoreactive varicosities in the dorsal pallidum. The distribution pattern of alpha 1 subunit-like immunoreactivity reflects a partial overlap with the substance P and enkephalin system although a differential distribution to each of these peptides was observed for cell bodies, fibers, and axon terminals.
Marksteiner
J
J
Neurochemical Unit, Clinic of Psychiatry, Innsbruck, Austria.
Lassnig
E
E
Humpel
C
C
Sieghart
W
W
Kaufmann
W
W
Saria
A
A
D000818:Animals; D004745:Enkephalins / Q000276:immunology*; D007150:Immunohistochemistry; D008297:Male; D016548:Prosencephalon / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000276:immunology / Q000378:metabolism*; D013373:Substance P / Q000276:immunology*
D004745:Enkephalins; D011963:Receptors, GABA-A; D013373:Substance P