Beta2-adrenergic receptor agonists reduce proliferation but not protein synthesis of periodontal fibroblasts stimulated with platelet-derived growth factor-BB

OBJECTIVE Catecholamines released from β-adrenergic neurons upon stress can interfere with periodontal regeneration. The cellular mechanisms, however, are unclear. Here, we assessed the effect of catecholamines on proliferation of periodontal fibroblasts. METHODS Fibroblasts from the gingiva and the periodontal ligament were exposed to agonists of the β-adrenergic receptors; isoproterenol (ISO, non-selective β-adrenergic agonist), salbutamol (SAL, selective β2-adrenergic receptor agonist) and BRL 37344 (BRL selective β3-receptor agonist). Proliferation was stimulated with platelet-derived growth factor-BB (PDGF-BB). Pharmacological inhibitors and gene expression analysis further revealed β-adrenergic signalling. RESULTS Gingiva and periodontal ligament fibroblast express the β2-adrenergic receptor. ISO and SAL but not BRL decreased proliferation of fibroblasts in the presence of PDGF-BB. The inhibitory effect of β-adrenergic signalling on proliferation but not protein synthesis in response to PDGF-BB was reduced by propranolol, a non-selective β-adrenergic antagonist. CONCLUSIONS These results suggest that β2-receptor agonists can reduce the mitogenic response of periodontal fibroblasts. These data add to the compelling concept that blocking of β2-receptor signalling can support tissue maintenance and regeneration.