Differences in ME-LI and VIP-LI in discrete brain regions of seizure-naive and seizure-experienced El mice.
In an attempt to elucidate the relationship between endogenous methionine-enkephalin (ME) and vasoactive intestinal polypeptide (VIP) with generalized seizures, we determined regional brain levels of ME-like and VIP-like immunoreactivity (ME-LI and VIP-LI) in El mice during and after seizures induced by repeated tossing stimulation. The levels of ME-LI in the striatum and hippocampus of seizure-naive El mice (El-) were lower than those of the control ddY mice, the mother strain of El mice. Conversely, the level of VIP-LI in the medulla oblongata and pons of El- was higher than that of ddY mice. The level of ME-LI in the striatum of seizure-experienced El mice (El+) killed 96 hours after three consecutive seizures was high, while levels of VIP-LI in the striatum and hypothalamus were low, in comparison to those of El- mice. A detailed time-course study revealed that seizures in El mice caused (1) significant decreases in levels of ME-LI in the striatum and hippocampus during seizures, (2) a significant decrease of VIP-LI content in the striatum 3 hours after seizures, and (3) a significant increase in hypothalamic VIP-LI 9 hours after seizures. These observations suggest that ME and VIP may play some role in El mouse seizures.
Kanamatsu
T
T
Department of Physiology, Toho University School of Medicine, Tokyo, Japan.
Hirano
S
S
D000818:Animals; D001921:Brain / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000378:metabolism*; D008297:Male; D051379:Mice; D008818:Mice, Neurologic Mutants; D011863:Radioimmunoassay; D012640:Seizures / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D014660:Vasoactive Intestinal Peptide; D004744:Enkephalin, Methionine