Somatostatin modulates mast cell‐induced responses in murine spinal sensory neurons and satellite cells

Abstract

The expression of somatostatin (SOM) receptors (SSTRs) in mucosal mast cells and sensory nerve fibers suggests a modulatory effect for this peptide in the mast cell‐neuron communication. Therefore, the modulatory effects of SOM on the short‐term and long‐term effects induced by histamine (HIS) and serotonin (5‐HT) on sensory neuronal characteristics were assessed using murine spinal neuronal cultures.ELISA and live cell imaging demonstrated acute HIS‐ and 5‐HT‐induced neuronal CGRP release and calcium‐mediated activation of both neurons and non‐neuronal cells. Both of these effects were strongly reduced by preincubating the spinal cultures with SOM. Long‐term incubation of the spinal cultures with HIS and 5‐HT significantly elevated neuronal expression of substance P, CGRP and SOM as demonstrated by qPCR and quantitative analysis. Also these long‐term effects of HIS and 5‐HT were partly inhibited by chronic SOM exposure. Immunocytochemistry and RT‐PCR revealed the involvement of SSTR1 and SSTR2A in these SOM‐dependent effects.The data demonstrate an interfering effect of SOM on the mast cell‐neuron communication, implying a major role for this peptide in intestinal inflammatory responses. Since SOM affects HIS‐ and 5‐HT‐induced responses in non‐neuronal cells as well, SOM could indirectly modulate sensory neuronal characteristics through modulation of the surrounding non‐neuronal cells.