The present status of the mechanical hypothesis for chemoreceptor stimulation.

Reasons are given to show why the transmitter based hypothesis for the stimulation of chemoreceptors needs to be reviewed. On the other hand evidence is presented to show that chemoreceptors can be stimulated by various mechanical stimuli and how the local PO2 can be sensed by the type II cell which by getting mechanically deformed causes this cell to shrink. This shrinkage is transmitted to the generator region of the nerve terminal thereby leading to the production of propagated impulses at the regenerative region thus making the whole process of generation of information about the local PO2, similar to the generation of sensory information by other sensory receptors.