Bacterially derived SCFAs do not affect contractions or injure nNOS neurons in cultured intact duodenal muscularis externa. A, The number of muscle contractions per second was not affected by 24 hours of treatment with 30mM concentrations of SCFAs when compared with untreated control samples. B-C, SCFAs did not affect the percentage of nNOS neurons per total number of neurons in myenteric ganglia and the number of myenteric of nNOS neurons per ganglionic area after 24 hours. D, Sample images showing overlays of nNOS (red) and ANNA1 (green) staining in duodenal myenteric ganglia of untreated control, acetate, propionate and butyrate treated duodenal muscularis externa.