Effects of hormones and cytokines on stimulation of adenylate cyclase and intracellular calcium concentration in human and canine periodontal-ligament fibroblasts

Summary-Adenylate cyclase was stimulated by prostaglandin E, (PGE,) and parathyroid hormone-related protein (PTHrP) in both these types of fibroblast and by calcitonin gene-related protein (CGRP) in the human fibroblasts in vitro. PGE, (1 PM), CGRP (1 hM), and PTHrP (1 PM) stimulated adenylate cyclase up to 50-fold, IO-fold and 9-fold, respectively. Calcitonin (CT), substance P (SP), interleukin-lb (IL-l/3 ), and transforming growth factor-& (TGF/?,) had no effect on adenylate cyclase in either fibroblast. Intracellular Ca*+ (iCa*+ ) was measured in individual fibroblasts from the periodontal ligament using Indo-l and an adherent cell analysis and sorting interactive laser cytometer. Ionomycin (3 PM) caused a transient rise of iCa*+ m all human and canine fibroblasts tested. The mean percentage increase in iCaz+ in response to ionomycin was 820 and 840% for human and canine fibroblasts, respectively. The human fibroblasts responded to PGE, (1 PM) by an increased iCa2+ concentration; the mean percentage increase in iCa2+ was 187%. SP caused a less pronounced increase in iCa*+ in the human fibroblasts (56%). CGRP and SP caused a similar response in the canine fibroblasts. The mean percentage increase in iCa*+ in response to SP and CGRP was 95 and 78%, respectively. PTH, PTHrP, platelet-activating factor, CT, and IL-IS had no effect on iCa *+ in either type of fibroblast. The data indicate that CAMP and calcium have roles as intracellular secondary messengers in the action of PGE,, SP, CGRP, and PTHrP in fibroblasts of human and canine periodontal ligament.