Again the owls hooted along the stream and bullfrogs croaked from the reedy places.
There was a flop in the water, and the bullfrog disappeared from sight.
Thus, we think that the possibility of an opsin difference between the porphyropsin and the rhodopsin of the bullfrog can be neglected.
Bullfrog retinal bipolar cells may express heterogeneous glycine receptors at dendrites and axon terminals.
Glycinergic synaptic transmission to bullfrog retinal bipolar cells is input-specific.