Nicotine-induced dystonic arousal complex in a mouse line harboring a human autosomal-dominant nocturnal frontal lobe epilepsy mutation.
We generated a mouse line harboring an autosomal-dominant nocturnal frontal lobe epilepsy (ADNFLE) mutation: the alpha4 nicotinic receptor S248F knock-in strain. In this mouse, modest nicotine doses (1-2 mg/kg) elicit a novel behavior termed the dystonic arousal complex (DAC). The DAC includes stereotypical head movements, body jerking, and forelimb dystonia; these behaviors resemble some core features of ADNFLE. A marked Straub tail is an additional component of the DAC. Similar to attacks in ADNFLE, the DAC can be partially suppressed by the sodium channel blocker carbamazepine or by pre-exposure to a very low dose of nicotine (0.1 mg/kg). The DAC is centrally mediated, genetically highly penetrant, and, surprisingly, not associated with overt ictal electrical activity as assessed by (1) epidural or frontal lobe depth-electrode electroencephalography or (2) hippocampal c-fos-regulated gene expression. Heterozygous knock-in mice are partially protected from nicotine-induced seizures. The noncompetitive antagonist mecamylamine does not suppress the DAC, although it suppresses high-dose nicotine-induced wild-type-like seizures. Experiments on agonist-induced 86Rb+ and neurotransmitter efflux from synaptosomes and on alpha4S248Fbeta2 receptors expressed in oocytes confirm that the S248F mutation confers resistance to mecamylamine blockade. Genetic background, gender, and mutant gene expression levels modulate expression of the DAC phenotype in mice. The S248F mouse thus appears to provide a model for the paroxysmal dystonic element of ADNFLE semiology. Our model complements what is seen in other ADNFLE animal models. Together, these mice cover the spectrum of behavioral and electrographic events seen in the human condition.
Teper
Yaroslav
Y
Howard Florey Institute, The University of Melbourne, Victoria 3010, Australia.
Whyte
Douglas
D
Cahir
Elizabeth
E
Lester
Henry A
HA
Grady
Sharon R
SR
Marks
Michael J
MJ
Cohen
Bruce N
BN
Fonck
Carlos
C
McClure-Begley
Tristan
T
McIntosh
J Michael
JM
Labarca
Cesar
C
Lawrence
Andrew
A
Chen
Feng
F
Gantois
Ilse
I
Davies
Philip J
PJ
Petrou
Steven
S
Murphy
Mark
M
Waddington
John
J
Horne
Malcolm K
MK
Berkovic
Samuel F
SF
Drago
John
J
D000818:Animals; D001143:Arousal / Q000187:drug effects / Q000235:genetics*; D004195:Disease Models, Animal; D020821:Dystonic Disorders / Q000139:chemically induced / Q000235:genetics*; D017034:Epilepsy, Frontal Lobe / Q000139:chemically induced / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008818:Mice, Neurologic Mutants; D008822:Mice, Transgenic; D009154:Mutation; D009538:Nicotine / Q000633:toxicity*; D051381:Rats; D013045:Species Specificity; D014981:Xenopus
D009538:Nicotine