Ionic Stimulation of the Olfactory Epithelium in the Bullfrog and the Carp

Sadayuki F. TAKAGI, Masae IINO, Hiroshi YARITA, Kensaku MORI
1978 The Japanese Journal of Physiology  
The stimulating effects of mono-and divalent cations and anions were studied in the olfactory epithelia of the bullfrog and the carp. The rhythmic waves induced by these ions were recorded in the olfactory bulb. 1. Many mono-and divalent cations and anions showed stimulating actions in the bullfrog and the carp. 2. Microelectrode studies disclosed that the olfactory receptor cells respond to different ions differently. 3. When many ions were applied with various concentrations, responses
more » ... d with long latencies while the concentration was very low (the "delayed responses"). The responses nearly disappeared at the intermediate concentrations, but then responses with short latencies appeared at the higher concentrations (the "initial responses"). Thus, many ions showed dual responses in the bullfrog, although some exceptional cases were found (choline+, Tl+, La3+, Cd2+) 4. Cd2+ and other heavy metal ions showed depressive actions upon the responses induced by other ions in the olfactory epithelium. 5. Tetrodotoxin of even 10-5 g/ml was found ineffective in depressing the rhythmic waves induced by ions. 6. Chemoreceptive activities of the olfactory epithelia of the bullfrog and the carp were compared with the activities of the gustatory receptors. They were also compared with the other chemoreceptors of the fish, namely the palatal organ, external chemoreceptors over the snout region and the lateral-line organ. Chemical senses of the fish were discussed. The olfactory epithelium in terrestrial animals and fish has generally been supposed to be a receptor of odorous substances in vapor and aqueous phases, respectively. Is this supposition correct? In fact, this assumption has often been challenged. Thus, UEKI and DOMINO (1961) proved in the dog that rhythmic waves are elicited in the olfactory bulb, when not only various odors but also
doi:10.2170/jjphysiol.28.129 fatcat:4k5uqprkdneerhd2ea35uhzsoi