Uses
It is a cholinesterase inhibitor for treating and preventing migraine. An antimigraine agent.
Biological Activity
migraine is a common, recurrent and primary headache disorder. optimisation of novel cis- and trans-4-(substituted-anfido)benzopyran-3-ol derivatives has led to the identification of tonabersat (sb-220453) with potential antimigraine activity.
Biochem/physiol Actions
Tonabersat (SB-220453) exhibits anticonvulsant property. It is a member of the family of novel benzoylamino-benzopyran compounds. Tonabersat is used as a therapeutic for trigeminal nerve-induced neurovascular reflexes. In addition, it acts as a putative migraine prophylactic agent containing an unique stereospecific binding site in the brain.
in vitro
topiramate targets multiple cortical and subcortical loci, altering voltage-gated ion channels and chemical transmission to decrease abnormal brain excitability. preclinical studies have identified four properties that may account for the drug’s efficacy in epilepsy and migraine prophylaxis: (i) blockage of voltage-dependent sodium channels; (ii) augmentation of the activity of the neurotransmitter g-aminobutyric acid (gaba) at some subtypes of the gaba-a receptor; (iii) antagonism of the ampa/kainate subtype of the glutamate receptor; and (iv) inhibition of the carbonic anhydrase enzymes, particularly isozymes ii and iv [1].
in vivo
tonabersat binds selectively to a unique site in the brain. moreover, tonabersat could markedly reduce cortical spreading depression (csd) and csd-associated events and inhibite gap-junction communication between neurons and satellite glial cells in the trigeminal ganglion. together, these findings indicate that tonabersat should have clinical application in preventing migraine attacks [2].
References
[1] silberstein sd. tonabersat, a novel gap-junction modulator for the prevention of migraine. cephalalgia. 2009;29 suppl 2:28-35.
[2] durham pl, garrett fg. neurological mechanisms of migraine: potential of the gap-junction modulator tonabersat in prevention of migraine. cephalalgia. 2009;29 suppl 2:1-6.
[3] hauge aw, asghar ms, schytz hw, christensen k, olesen j. effects of tonabersat on migraine with aura: a randomised, double-blind, placebo-controlled crossover study. lancet neurol. 2009;8(8):718-23.
