GABA-like immunoreactivity in the tuberomammillary nucleus: an electron microscopic study in the rat.
The organization of GABAergic elements in the histaminergic tuberomammillary nucleus has been examined by using antibodies against gamma-aminobutyric acid (GABA) and light and electron microscopy. Most neuronal perikarya of the ventral subgroup of the tuberomammillary nucleus were GABA immunoreactive (GABA-i). The morphology of the GABA-i perikarya was similar to the morphology of histaminergic perikarya described by Hayashi et al. ('84: J. Comp. Neurol. 229: 223-241) and Wouterlood et al. ('86: J. Comp. Neurol. 252:227-243). The GABA-i perikarya were contacted by relatively few terminals. The mean bouton covering ratio of GABA-i perikarya was 6.1%, whereas the mean bouton covering ratio for GABA-i dendrites in the tuberomammillary nucleus was 31%. Some of the presynaptic terminals were GABA-i. In addition, GABA-i perikarya and dendrites formed close contacts that never presented synaptic specializations. These results suggest that neurons of the histaminergic tuberomammillary nucleus contain the neurotransmitter GABA. Furthermore, GABA may act as a modulator of cellular processes within the tuberomammillary nucleus.
Ericson
H
H
Department of Human Anatomy, Biomedical Center, Uppsala, Sweden.
Köhler
C
C
Blomqvist
A
A
D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure*; D003712:Dendrites / Q000648:ultrastructure; D007026:Hypothalamic Area, Lateral / Q000166:cytology / Q000648:ultrastructure*; D008297:Male; D016253:Microscopy, Immunoelectron / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
D005680:gamma-Aminobutyric Acid