AJP - Regulatory, Integrative and Comparative Physiology, Vol 244, Issue 2 176-R186, Copyright © 1983 by American Physiological Society
Ionic distribution in dopamine-stimulated NaCl fluid-secreting cockroach salivary glands
B. L. Gupta and T. A. Hall
The compound, racemose, innervated salivary glands of the cockroach
Periplaneta americana closely resemble in structure and function the
mammalian salivary glands (C.R. House, Biol. Rev. 55: 417-473, 1980). The
quantitative distribution of Na, K, Cl, Ca, Mg, P, and S was investigated
in the P-cells secreting isotonic NaCl and in duct lumens by using electron
probe X-ray microanalysis of frozen-hydrated and frozen-dried cryosections.
In the unstimulated glands in vitro the cells had (mmol/l cell-H2O) Na, 10;
K, 110; Cl, 39 while the primary saliva had Na, 153; K, 4; Cl, 151. With 1
mumol dopamine in the bathing Ringer solution the P-cells had Na, 25; K,
177; Cl, 58 and the primary saliva, Na, 153; K, 26; Cl, 172. During passage
through the ducts, the primary saliva was modified by an absorption of
NaCl: more in unstimulated than in stimulated glands. It is proposed that
the cells have a Na-K-ATPase both in the apical and basal cell membrane, as
in vertebrate choroid plexus, and dopamine might increase the K and Na
conductance of the basal cell membrane.
