AJP - Cell Physiology, Vol 235, Issue 3 128-C135, Copyright © 1978 by American Physiological Society
Calcium and the control of potassium efflux in the sublingual gland
J. W. Putney Jr, B. A. Leslie and S. H. Marier
The effects of cholinergic stimulation on K efflux from rat sublingual
gland slices was investigated. The sublingual gland slices appeared stable
on incubation as indicated by electrolyte content and ultrastructural
analysis. Carbachol induced a biphasic increase in release of 86Rb (an
index of K efflux); a transient phase lasting 2--4 min was followed by a
sustained (or slowly falling) phase. Both phases of the response were
blocked by atropine, but only the sustained phase was blocked by omission
of Ca or by the addition of LaCl3. The divalent cationophore A-23187
produced a Ca-dependent release of 86Rb. Substance P stimulated a biphasic
release of 86Rb, similar to that obtained with carbachol, but epinephrine
did not. The response to substance P demonstrated a Ca dependence similar
to that of carbachol. When a transient response to carbachol was elicited,
no transient response to carbachol was elicited, no transient response to
substance P could be obtained. This suggests that the receptors for these
agonists may reside in the same cells. Also, the magnitude of the responses
suggests that most of the affected cells are probably the mucous elements
of the sublingual gland.
