title: The effects of linalool on the excitability of central neurons of snail Caucasotachea atrolabiata.
abstract: Linalool is a major constituent of the essential oil of several plant species and possesses several biological activities. In this work, we studied the effects of linalool on excitability of central neurons of land snail Caucasotachea atrolabiata and tried to elucidate the underlying mechanisms. The lower concentration of linalool (0.1mM) showed suppressive action on spontaneous activity and pentylenetetrazole-induced epileptiform activity. These effects were associated with elevation of the action potential threshold and reduction of action potential rising phase, supporting the inhibitory action of linalool on Na+channels. At this concentration it also prolonged the post stimulus inhibitory period that can take part in its antiepileptic effect and apparently results from increased action potential duration and indirect augmentation of Ca2+-activated K+currents. At higher concentration, however, linalool (0.4mM) increased the neuronal excitability and induced epileptiform activity. The modulatory effects on action potential waveform during preconvulsive period suggest that the recent effect is mainly dependent on the suppression of outward potassium currents underlying repolarization phase and afterhyperpolarization. The linalool-induced epileptiform activity was abolished by Ca2+channel blockers, nifedipine and nickel chloride, and selective inhibitor of protein kinase C, chelerythrine, suggesting that Ca2+inward currents and protein kinase C (PKC) activity are required for linalool-induced epileptiform activity. Our results support the antiepileptic activity of linalool at lower dose, but it shows epileptogenic activity when applied directly on snail neurons at higher dose. Linalool may also be a potential therapeutic agent for activating PKC.
authors.affiliation: Department of Biology, Shiraz University, Shiraz, Iran. Electronic address: vatanparast@shirazu.ac.ir.
authors.forename: Jafar
authors.initials: J
authors.lastname: Vatanparast
authors.affiliation: Department of Biology, Shiraz University, Shiraz, Iran.
authors.forename: Sara
authors.initials: S
authors.lastname: Bazleh
authors.affiliation: Neuroscience Research Center and Department of Physiology, Medical School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Mahyar
authors.initials: M
authors.lastname: Janahmadi
mesh_terms: D000200:Action Potentials; D000080462:Acyclic Monoterpenes; D000818:Animals; D000927:Anticonvulsants / Q000633:toxicity*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002490:Central Nervous System / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004827:Epilepsy / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D039821:Monoterpenes / Q000633:toxicity*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010433:Pentylenetetrazole; D011493:Protein Kinase C / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012908:Snails; D013997:Time Factors
chemical_list: D000080462:Acyclic Monoterpenes; D000927:Anticonvulsants; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D039821:Monoterpenes; D047428:Protein Kinase Inhibitors; C018584:linalool; D011493:Protein Kinase C; D010433:Pentylenetetrazole
keywords: Antiepileptic; Epileptiform activity; Ion channels; Kinase C; Linalool; Protein; Snail neuron