Transient changes in the limbic histaminergic system after systemic kainic acid-induced seizures.
Increased brain histamine is reported to protect against convulsions. We used systemic kainic acid (KA) administration to study possible changes of the histaminergic system in rat brain in status epilepticus (SE). Robust increases in brain histamine concentrations and numbers of histamine-immunoreactive nerve fibers were detected in the piriform cortex (Pir) and amygdala after KA injection, suggesting a reactive increase, which is opposite to other published aminergic transmitter responses. These changes, lasting several weeks, might be coupled to a mechanism unrelated to the anticonvulsive function of histamine. Transient increases in mRNA expression of H(3) receptor isoforms with a full-length third intracellular loop, coupled to mitogen-activated protein kinase pathway, were detected first in the hippocampal CA3c area, followed by the Pir and amygdala and then the hippocampal CA1 area. These results suggest that histamine and H3 receptors, which also control the release of GABA and glutamate, might be involved in convulsive SE.
Lintunen
Minnamaija
M
Department of Biology, Abo Akademi University, Biocity, Tykistokatu 6A, FIN-20520 Turku, Finland.
Sallmen
Tina
T
Karlstedt
Kaj
K
Panula
Pertti
P
D000679:Amygdala / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D001369:Axons / Q000378:metabolism; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D006624:Hippocampus / Q000378:metabolism / Q000503:physiopathology; D006632:Histamine / Q000378:metabolism*; D007608:Kainic Acid; D008032:Limbic System / Q000378:metabolism* / Q000503:physiopathology; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D009434:Neural Pathways / Q000378:metabolism* / Q000503:physiopathology; D009833:Olfactory Pathways / Q000378:metabolism / Q000503:physiopathology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D018100:Receptors, Histamine H3 / Q000235:genetics; D013226:Status Epilepticus / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology; D015854:Up-Regulation / Q000502:physiology
D012333:RNA, Messenger; D018100:Receptors, Histamine H3; D006632:Histamine; D007608:Kainic Acid