Does the Miranda rule apply to a witness before a grand jury?

We are not here called upon to reexamine the rule announced by this court in Groshart v. United States, 392 F.2d 172 (9th Cir., 1968), pertaining to the use, for impeachment purposes, of statements obtained from a defendant in violation of the rule announced in Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694. Appellant, while present before the grand jury pursuant to a subpoena, was not then in police custody and the Miranda rules were for that reason not applicable to his grand jury interrogation.