Figure 8.

Model to explain insect olfactory neuron sensitization in basiconic sensilla. Following repeated stimulation with subthreshold odor concentrations of the OrX/Orco receptor complex in the olfactory cilia of the outer dendritic segment, CaM together with other unknown intracellular or membrane factors can lead to OR sensitization. This may lead to the observed ODS sensitization. Small currents originating from the ODS might trigger Ca²⁺ release from intracellular Ca²⁺ stores, including mitochondria and the endoplasmatic reticulum, first in the IDS and subsequently in the soma. In this way these cellular compartments become sensitized and the signal becomes more and more amplified. Finally, the membrane potential at the axon hillock reaches the action potentials threshold faster which enhances the firing rate.