Fig 3.

Microphysiometric characterization of rat corpus cavernosum cells. Primary cultures of rat smooth muscle cells from rat corpus cavernosum (and CHO cells stably expressing the rat MC4R) were tested for ligand-stimulated metabolic activation. The acidification rate (μVolt/s) was monitored during the addition of the indicated concentrations of the melanocortin agonists MTII, α-NDP-MSH, and MC4R agonist. Endothelin-1, an agonist of ET_A receptors present on smooth muscle cells, was used as a control. The values represent the rate of acidification compared with the unstimulated basal rate and are representative of three independent experiments.