Trigeminal satellite cells express functional calcitonin gene-related peptide receptors, whose activation enhances interleukin-1β pro-inflammatory effects

Calcitonin gene-related peptide (CGRP) is the main mediator of trigeminal pain signal. Functional CGRP receptors were detected in trigeminal satellite cells, a specialized type of glia found within the sensory ganglia. CGRP displayed modest pro-inflammatory effects per se on trigeminal satellite cells, while it significantly enhanced IL-1β actions, increasing the expression and activity of cycloxygenase 2 as well as the expression of the inducible form of nitric oxide synthase and IL-1β. CGRP effects were reverted by a specific CGRP receptor antagonist and mimicked by elevation of intracellular cAMP levels. CGRP exerted also minor proinflammatory effects on cortical astrocytes.