ABSTRACT
The primary process of carbon dioxide reception in the temporal organ of the Japanese house centipede Thereuonema hilgendorfi has been studied by means of intracellular recording.
During adaptation to air containing no carbon dioxide, the membrane potential of receptor cells in the temporal organ ranged from –25 to –59 mV with an average of –39mV (N = 21). Input resistance ranged from 10 to 46MQ with an average of 22-6MQ (N= 16).
Receptor cells responded to a carbon dioxide stimulus with a graded hyperpolarizing receptor potential, which reduced impulse frequency. The decrease in steady-state frequency was proportional to the amplitude of the receptor potential.
During the receptor potential, the input resistance increased. Injection of hyperpolarizing current resulted in an increase in amplitude of receptor potential, while depolarizing current caused a decrease. These results suggest that the receptor potential is caused by a decrease in membrane permeability to ions whose equilibrium potential is more positive than the membrane potential adapted to 0 % carbon dioxide.
