Electrical Responses to Chemical Stimulation of Squid Olfactory Receptor Cells

Electrical properties of isolated olfactory receptor cells were studied using voltageand current-clamp techniques based on whole-cell patch-clamp methods. Squid olfactory receptor cells contain voltage-gated Na and K channels and are capable of generating action potentials. Chemicals that elicit escape-jetting responses in behavioral experiments affect the excitability of isolated receptor cells. One set of such chemicals, including quaternary ammonium ions and aminopyridines, blocks K channels and increases excitability. Squid ink and L-Dopa also elicit escape jetting, but these substances increase membrane conductance, hyperpolarize the receptor cell and decrease excitability. These experiments indicate that sensory neurons of the olfactory organ are capable of detecting chemical signals and that at least two different transduction mechanisms can lead to similar behavioral responses.