Hypertension, Vol 17, 303-307, Copyright © 1991 by American Heart Association
PA Craven and FR DeRubertis
Renomedullary interstitial cells cultured from the Dahl salt-resistant rat
have higher levels of basal cytosolic calcium and prostaglandin E2 and are
more responsive to vasopressin than interstitial cells from the Dahl
salt-sensitive rat. We examined the potential role of inositol phospholipid
hydrolysis in mediating these differences. Vasopressin- induced increases
in labeled inositol phosphates were enhanced in renomedullary interstitial
cells from Dahl salt-resistant compared with those from salt-sensitive
rats. Addition of neomycin reduced basal production of labeled inositol
phosphates and abolished the increase in inositol phosphates induced by
vasopressin. Neomycin also prevented the peak decline pattern in cytosolic
Ca2+ seen with vasopressin but did not influence basal cytosolic Ca2+. In
the presence of neomycin, vasopressin induced a modest but prolonged
increase in cytosolic calcium. In contrast to its marked effects on
inositol phosphate production, neomycin was without effect on basal or
vasopressin- responsive prostaglandin E2 production. Moreover, basal and
vasopressin- induced increases in cytosolic Ca2+ remained higher in
renomedullary interstitial cells from Dahl salt-resistant versus those from
salt- sensitive rats exposed to neomycin. The results do not support a
requirement for phospholipase C-induced inositol phospholipid hydrolysis in
the mediation of vasopressin actions on prostaglandin E2 production by
renomedullary interstitial cells and imply that the differences in
cytosolic Ca2+ and prostaglandin E2 seen in these two cell lines are not
related to differences in inositol phospholipid metabolism.
ARTICLES
Calcium and prostaglandin E2 in renomedullary interstitial cells
Department of Medicine, University of Pittsburgh, Pa.
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