Temperature and species-specific effects on ß3-adrenergic receptor cardiac regulation in two freshwater teleosts: Channel catfish (Ictalurus punctatus) and common carp (Cyprinus carpio)

Stimulation of β3-ARs in 23 °C acclimated channel catfish (Ictalurus punctatus) caused significant increases in fH, Sv and Q. The increase in Sv was opposite to the decrease observed in 23 °C acclimated common carp. SR59230A induced significant decreases in Sv and Q but had no effect in carp (23 °C). Results suggest species diversity in the density and affinity or structure of ß3-ARs which may explain the different cardiac responses to ß3-AR ligands.