Galanin gene transfer curtails generalized seizures in kindled rats without altering hippocampal synaptic plasticity

• Published in: Neuroscience 2007-12, Vol.150 (4), p.984-992
• Main Authors: Kanter-Schlifke, I, Toft Sørensen, A, Ledri, M, Kuteeva, E, Hökfelt, T, Kokaia, M
• Format: Article
• Language: English
• Subjects: Animals; Basic Medicine; Biological and medical sciences; Dependovirus - physiology; Disease Models, Animal; Dose-Response Relationship, Radiation; Electric Stimulation - adverse effects; epilepsy; Excitatory Postsynaptic Potentials - drug effects; Excitatory Postsynaptic Potentials - physiology; Excitatory Postsynaptic Potentials - radiation effects; Fundamental and applied biological sciences. Psychology; galanin; Galanin - biosynthesis; Galanin - physiology; gene therapy; Gene Transfer Techniques; Genetic Vectors - physiology; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Hippocampus - physiopathology; Hippocampus - radiation effects; kindling; Kindling, Neurologic - physiology; Male; Medical and Health Sciences; Medical sciences; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Nervous system (semeiology, syndromes); Neurology; Neuronal Plasticity - physiology; Neurosciences; Neurovetenskaper; rAAV; Rats; Rats, Sprague-Dawley; Reaction Time; Seizures - etiology; Seizures - pathology; Seizures - therapy; synaptic plasticity; Time Factors; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544; 1873-7544
• DOI: 10.1016/j.neuroscience.2007.09.056

Abstract Gene therapy–based overexpression of endogenous seizure-suppressing molecules represents a promising treatment strategy for epilepsy. Viral vector–based overexpression of the neuropeptide galanin has been shown to effectively suppress generalized seizures in various animal models of epilepsy. However, it has not been explored whether such treatment can also prevent the epileptogenesis. Using a recombinant adeno-associated viral (rAAV) vector, we induced hippocampal galanin overexpression under the neuron specific enolase promoter in rats. Here we report that in animals with galanin overexpression, the duration of electrographic afterdischarges was shortened and initiation of convulsions was delayed at generalized seizure stages. However, the hippocampal kindling development was unchanged. Short-term plasticity of mossy fiber–cornu ammonis (CA) 3 synapses was unaltered, as assessed by paired-pulse and frequency facilitation of field excitatory postsynaptic potentials (fEPSPs) in hippocampal slices, suggesting that despite high transgene galanin expression, overall release probability of glutamate in these synapses was unaffected. These data indicate that hippocampal rAAV-based galanin overexpression is capable of mediating anticonvulsant effects by lowering the seizure susceptibility once generalized seizures are induced, but does not seem to affect kindling development or presynaptic short-term plasticity in mossy fibers.