Freeze-fracture cytochemistry of sympathetic ganglia. Distribution of filipin and tomatin induced membrane deformations in neurons and satellite cells.

Application of filipin to sympathetic ganglia results in membrane deformations in both the neurons and the satellite cells. The plasma membranes of the principal ganglion cells show a non-homogeneous distribution of filipin induced deformations with fewer deformations in the perikaryal plasma membrane than in the nerve fiber membrane. The filipin induced membrane lesions are correlated to the number of IMPs of the neuronal membrane i.e. a high density of intramembrane particles (IMP) gives fewer deformations and vice versa. The membrane of the satellite cells contain a higher density of probe induced lesions than the neuronal membrane. The filipin induced deformations in the satellite cells are not correlated to the number of IMPs or to the number of orthogonal arrays of small particles (OAP). Specialized membrane areas such as the gap junction is always devoided of filipin induced lesions. A similar distribution of membrane lesions was found when tomatin was used instead of filipin. These results indicate a possible difference in lipid content between various parts of the neurons and between the neuronal and satellite cell plasma membrane in guinea pig sympathetic ganglia.