Methods for treating neural cell swelling
A composition comprising a novel Ca 2+ -activated, [ATP] i -sensitive nonspecific cation (NC Ca-ATP ) channel is described. The channel is found in mammalian neural cells and exhibits a different sensitivity to block by various adenine nucleotides, and is activated by submicromolar [Ca] i . The NC Ca-ATP channel is activated under conditions of ATP depletion, which causes severe cell depolarization, followed by cell swelling. The NC Ca-ATP channel is regulated by a sulfonylurea receptor and is inhibited by sulfonylurea compounds glibenclamide and tolbutamide. Methods employing compositions comprising the NC Ca-ATP channel to screen for compounds that block the channel and the use of such antagonists as therapeutics in preventing brain swelling and damage are described. In addition, methods employing compositions comprising the Kir2.3 channel to screen for compounds that open the channel and the use of such antagonists as therapeutics in preventing brain swelling and damage are described.
1. A method of treating a subject having brain injury or cerebral ischemia, comprising the step of administering an antagonist of a NC ca-ATP channel that blocks the channel, prevents the channel opening, and/or reduces the magnitude of membrane current through the channel, wherein the antagonist is a sulfonylurea compound or a benzamido derivative.
2. The method of claim 1 , wherein the cerebral ischemia is stroke.
3. A method of treating a subject having brain injury or cerebral ischemia by administering to the subject an antagonist of a NC ca-ATP channel in a dose at a substantially constant level for a given period of time, wherein the antagonist is a sulfonylurea compound or a benzamido derivative.
4. The method of claim 3 , wherein the cerebral ischemia is stroke.
5. The method of claim 3 , wherein the given period of time is about six or more hours.
6. The method of claim 3 , wherein the given period of time is about twelve or more hours.
7. The method of claim 3 , wherein the given period of time is about twenty-four or more hours.
8. A method of treating brain swelling in an individual, comprising the step of administering to the individual a compound that modulates NC Ca-ATP channel activity, wherein the compound is a sulfonylurea compound or a benzamido derivative.
9. A method of treating a subject for central or peripheral nervous system damage, said damage comprising depolarization due to expression of a NC Ca-ATP channel in neural cells, said method comprising administering to the subject a formulation comprising an effective amount of a compound effective to inhibit a NC Ca-ATP channel in the neural cells and a pharmaceutically acceptable carrier, wherein the compound is a sulfonylurea receptor 1 (SUR1) antagonist selected from a sulfonylurea compound or a benzamido derivative, and a combination thereof, wherein said administration of the SUR1 antagonist inhibits the activity of said NC Ca-ATP channel in neural cells expressing the channel.