Improved demonstration of exocytotic profiles in glomus cells of rat carotid body after perfusion with glutaraldehyde fixative containing a high concentration of potassium.
Extensive secretion by exocytosis was demonstrated in the glomus (type I) cells of the adult rat after perfusion of carotid bodies with a potassium-rich (high K) glutaraldehyde fixative. Similar secretory profiles were very rare with a glutaraldehyde fixative containing a low concentration of potassium (low K). The increase in the incidence of exocytotic profiles in glomus cells with the high K fixative was highly significant, whereas no statistical difference could be observed in the incidence of coated pits with the different fixatives. Exocytotic profiles were characterized by the following features: (1) they predominated in non-synaptic regions, but were occasionally observed near synapses between two glomus cells; they were not observed near synapses between glomus cells and nerve terminals; (2) extruded electron-dense material associated with coating of the cell membrane was frequent; (3) different stages of dissolution of the extruded granule material was evident. The possible role of exocytosis as a mode of secretion in the glomus cells and the characteristics of the new high K-glutaraldehyde fixative are discussed.
D000818:Animals; D002344:Carotid Body / Q000378:metabolism* / Q000648:ultrastructure; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism / Q000648:ultrastructure; D005089:Exocytosis; D005260:Female; D005404:Fixatives; D005976:Glutaral; D008297:Male; D008854:Microscopy, Electron; D011188:Potassium; D051381:Rats; D011919:Rats, Inbred Strains
D005404:Fixatives; D011188:Potassium; D005976:Glutaral