Odor discrimination of 'cAMP-' and 'IP3-increasing' odorants at high temperature and at high NaCl concentration in...

The ability of the turtle olfactory system to discriminate between various cAMP- and IP3-increasing odorants at high temperature and at high NaCl concentration in the olfactory bulb was examined by the cross-adaptation technique. The degrees of discrimination in high [Na+] solution were similar to those in normal Ringer's solution, suggesting that selectivities of receptors coupled with cAMP- and IP3-dependent pathways are similar to those coupled with both cAMP- and IP3-independent pathways. The mean values of the degree of discrimination among the IP3-increasing odorants were higher than those among the cAMP-increasing odorants at high temperature and at high [Na+] concentration. The degrees of discrimination among the IP3-increasing odorants at 40 degrees C were greater than those at 25 degrees C, while those among the cAMP-increasing odorants at 40 degrees C were similar to those at 25 degrees C, suggesting that the features of the receptors of cAMP-increasing odorants are different from those which respond to IP3-increasing odorants.