Ultrastructural characteristics of freeze-dried smooth muscle

The rapid freezing and vacuum dehydration of tissue has been employed to study the intracellular distribution of diffusible substances at the electron microscopic level. Hower, the ultrastructural detail of freeze-dried tissue is difficult to retain. Consequently, the ultrastructural preservation of freeze-dried smooth muscle has not been sufficient to permit satisfactorily definition of intracellular organelles. Therefore, determinations of the intracellular distribution of soluble ions have not been achieved in freeze-dried smooth muscle. In this study a freeze drying method is presented which provides more satisfactory definition of intracellular organelles than has been available in the past. Using this merens have been preserved. When these muscles are compared to convention preparer of surface vesicles that are observed, and the mitochondria are extremely electron opaque in the freeze-dried tissue. The smooth muscles which have been examined do not have the inherent contrast of other types of tissue nor do they contain the different types of mitochondria that have been observed in nonmuscle tissue.