Central bombesin activates adrenal adrenaline- and noradrenaline-containing cells via brain thromboxane A2 in rats

The sympathetic nervous system regulates peripheral organs via the adrenal chromaffin cells containing adrenaline (A-cells) or noradrenaline (NA-cells) and the sympathetic ganglia. We examined the effect of intracerebroventricularly administered bombesin on neuronal activities of adrenal A-cells and NA-cells and several kinds of sympathetic ganglia (superior cervical, stellate and celiac ganglia) using c-Fos (a marker for neuronal activation), with regard to brain prostanoid, in anesthetized rats. Bombesin induced c-Fos in both adrenal A-cells and NA-cells, but not in any of the sympathetic ganglia. Central pretreatment with either indomethacin (a cyclooxygenase inhibitor) or furegrelate (a thromboxane A2 synthase inhibitor) abolished all bombesin-induced responses. These results suggest that bombesin centrally activates adrenal A-cells and NA-cells by brain thromboxane A2-mediated mechanisms in rats.