Gap junction blockade does not alter eupnea or gasping in the juvenile rat.

The role of gap junctions in the brainstem respiratory control system is ambiguous. In the present study, we used juvenile rats to determine whether blocking gap junctions altered eupnea or gasping in the in situ, arterially perfused rat preparation. Blockade of gap junctions with 100 microM carbenoxolone or 300 microM octanol did not produce any consistent changes in the timing or amplitude of integrated phrenic discharge or in the peak frequency in the power spectrum of phrenic nerve discharge during eupnea or ischemic gasping beyond those changes seen in time-control animals. These findings do not rule out a role for gap junctions in the expression of eupnea or gasping, but they do demonstrate that these intermembrane channels are not obligatory for either rhythm to occur.