Heat induced temperature dysregulation and seizures in Dravet Syndrome/GEFS+ Gabrg2+/Q390X mice

•A brief temperature rise evoked multiple types of seizures in Gabrg2+/Q390X mice.•A brief temperature rise evoked more myoclonic jerks in adolescent Gabrg2+/Q390X mice and more GTCSs in adult Gabrg2+/Q390X mice.•Gabrg2+/Q390X mice had altered thermoregulation as evidenced by more rapidly increased core temperature in adult than in adolescent Gabrg2+/Q390X mice.•Gabrg2+/Q390X mice had heightened anxiety with temperature elevation.•Seizure severity following temperature elevation was less than seizure severity following PTZ administration.

It has been established that febrile seizures and its extended syndromes like generalized epilepsy with febrile seizures (FS) plus (GEFS+) and Dravet syndrome have been associated with mutations especially in SCN1A and GABRG2 genes. In patients, the onset of FS is likely due to the combined effect of temperature and inflammation in genetically vulnerable individuals because fever is often associated with infection. Much effort has been spent to understand the mechanisms underlying fever induction of seizures. In addition to the role of cytokines in FS, previous studies in Scn1a+/− knockout mice, a model of Dravet syndrome, indicated that temperature elevation alone could result in seizure generation, and the effect of elevated temperature inducing seizures was age-dependent. Here, we report the thermal effect in a different mouse model of Dravet syndrome, the Gabrg2+/Q390X knockin mouse. We demonstrated age-dependent dysregulated temperature control and that temperature elevation produced myoclonic jerks, generalized tonic clonic seizures (GTCSs) and heightened anxiety-like symptoms in Gabrg2+/Q390X mice. The study indicated that regardless of other inflammatory factors, brief heat alone increased brain excitability and induced multiple types of seizures in Gabrg2+/Q390X mice, suggesting that mutations like GABRG2(Q390X) may alter brain thermal regulation and precipitate seizures during temperature elevations.