GABAergic afferents modulate proenkephalin mRNA expression in the guinea pig hypothalamic magnocellular dorsal nucleus.
The proenkephalin (PE) gene expression within Met-enkephalin (ME) neurons of the guinea pig magnocellular dorsal nucleus (MDN) was measured following activation of GABAergic transmission by aminooxyacetic acid treatment (AOAA). A combination of preembedding ME immunocytochemistry and PE in situ hybridization was used to investigate PE mRNA and enkephalin immunoreactivity levels. In perikarya of the MDN, chronic AOAA-treatment resulted in an important decline in PE mRNA signal (-128%). In double-labeled neurons, the PE mRNA decrease was associated to an increase in ME immunoreactivity. These results indicate that the increase in ME immunoreactivity in the MDN following AOAA-treatment is not due to a rise in PE gene transcription. This study provides additional morphological evidence supporting a role for GABA in modulating the enkephalinergic hypothalamoseptal tract of the guinea pig.
Mitchell
V
V
INSERM Unité 156, Lille, France.
Beauvillain
J C
JC
Mazzuca
M
M
D000625:Aminooxyacetic Acid / Q000494:pharmacology; D000818:Animals; D004302:Dorsomedial Hypothalamic Nucleus / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000378:metabolism; D004745:Enkephalins / Q000096:biosynthesis*; D006168:Guinea Pigs; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D066298:In Vitro Techniques; D008297:Male; D009475:Neurons, Afferent / Q000378:metabolism*; D011498:Protein Precursors / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D004745:Enkephalins; D011498:Protein Precursors; D012333:RNA, Messenger; C029992:proenkephalin; D000625:Aminooxyacetic Acid; D005680:gamma-Aminobutyric Acid; D004744:Enkephalin, Methionine