Retraction

For the article “Hydrogen Sulfide Is Produced in Response to Neuronal Excitation,” by Ko Eto, Miki Ogasawara, Ken Umemura, Yasuo Nagai, and Hideo Kimura, which appeared on pages 3386-3391 of the May 1, 2002 issue, the authors want to report the following: “The endogenous levels of hydrogen sulfide in CBS knock-out mice and the calmodulin dependency of CBS activity were underestimated. Our recent measurements show that the brains of CBS knock-out mice do contain some hydrogen sulfide, and that the dependency of CBS on calmodulin and glutamate is not critical. These errors were probably caused by the contamination by sulfur-containing substances in the serum albumin and the instability of the preparations used for gas chromatography.”