Tamotsu Tamura

Olfactory and gustatory responses to amino acids in two marine teleosts—Red sea bream and mullet

Abstract 1. The olfactory and gustatory responses to amino acids were recorded electrophysologically in two stocks of red sea bream ( Chrysophyrys major ) and mullet( Mugil cephalus ). 2. The olfactory spectra of amino acids determined from the bulbar response in the two stocks of red sea bream were more or less same, and the spectrum in mullet was also similar to that in the red sea bream. 3. A comparison of the spectra revealed high similarity among intra- and inter-species. 4. The gustatory spectra of amino acids were similar between the different two stocks of red sea bream, but the spectra were different from those obtained in other fishes. 5. The gustatory spectrum of amino acids in mullet was different from that in other fishes. 6. A comparison of the gustatory spectra revealed a species specificity. 7. From the view of the species non-specifycity of the olfactory spectrum of amino acids and the species specificity of the gustatory one, the functional difference between the olfactory and the gustatory response to amino acids in the feeding behaviour was discussed.

Origin of the slow potential in the pineal organ of the rainbow trout

Abstract The light-induced hyperpolarizing slow potential picked up by a glass microelectrode from the pineal organ, epiphysis cerebri, of the fish is concluded to be a receptor potential, for the following two reasons: (1) the potential showed practically no area effect as compared with the S-potential of the retina; and (2) injection of procion yellow through the recording electrode revealed that the tip of the electrode was in fact located in the photoreceptor cell when the potential was recorded. The hyperpolarizing potential was accompanied by a resistance decrease that reached a maximum of about 5M Ω on illumination.

Spectral sensitivity and color vision of fish as indicated by S-potential

Abstract 1. 1. Black porgy, chidai and neko shark seem to be color blind, since no chromatic type of S-potential was recorded in their retinas. 2. 2. From the presence of the chromatic responses in the retina, the ability to discriminate colors is thought to exist in mullet, carp, goldfish, suzuki, bluegill, yellow-tail and sting ray, and is especially well developed in the first three. 3. 3. A luminosity response, having a maximum between 584 and 612 mμ, was only found in carp, goldfish, bluegill and mullet. The high percentage of the occurrence of this response in these fishes suggests that they are most sensitive to the wavelengths around 600 mμ, which are also the prevailing wavelengths in their usual habitats. 4. 4. A shift of the maximum L-response to shorter wavelengths was observed in marine fishes such as suzuki, yellow-tail, sting ray, black porgy, chidai and neko shark. This is explained in terms of the adaptation to the environment where light of shorter wavelengths prevails. 5. 5. The S-potential method is suggested as a useful way to investigate color vision and spectral sensitivity of the fishes, especially those which are not suitable for training or behavioral experiments.

Olfactory responses to amino acids in marine teleosts

Abstract 1. 1. The olfactory responses to amino acids were recorded from the bulb of the red sea bream ( Chrysophyrys major ) and the conger eel ( Conger myriaster ). 2. 2. The threshold concentration for l -glutamine was 10 −7 M in the sea bream and below 10 −8 and 10 −9 M in the conger eel, and it was found that amino acids are good olfactory stimuli in both species. 3. 3. A comparison of the olfactory spectrum of amino acids of the sea bream with that of each of three species of freshwater fishes revealed a high similarity of spectra.

Effect of amino acids on the feeding behaviour in red sea bream

Abstract 1. The effects of amino acids and betaine on the feeding behaviour of red sea bream (Chrysophyrys major) were studied by adding the chemicals to a casein-base purified diet. 2. Among the 15 chemicals tested, 1 2 (alanine + betaine), 1 2 (glycine + betaine), l -alanine, l -valine, glycine, l -serine, l -arginine and l -glutamine were found to be effective in activating the feeding behaviour. 3. The behavioural experiments were concluded to harmonize well with the electrical activities of the gustatory system rather than those of the olfactory system.

The anterior cranial gustatory pathway in fish

Mit Hilfe elektrophysiologischer Methodik wurde anFugu pardalis geprüft, ob Geschmackssensationen von den Lippen über Trigeminus- oder Facialisfasern dem Gehirn übermittelt werden. Die Ergebnisse unterstützen die Ansicht, dass ausschliesslich der Facialisnerv bei diesem Vorgang beteiligt ist.

Pineal Photosensitivity in Fishes

The pineal organ or epiphysis cerebri develops embryonically as an evagination of the diencephalon in the same way as the retinas of the eyes. The pineal organ of fishes is located on the top of the brain, between the telencephalon and the optic tectum. In some species of fishes the head skin above the pineal is lacking in melanophores and translucent. The translucent region of the head skin was termed the “pineal window” by Rivas (1953).

Spectral Sensitivy Curves of the Skipjack Tuna and the Frigate Mackerel

The spectral sensitivity curves have been obtained by means of the L-response of S-potential for the skipjack tuna (Katsuwonus pelamis), and for the frigate mackerel (Auxis thazard). The sensitivity curve is always maximal at 497 nm and, in addition, differed little from the Dartnalls nomogram curve with its λmas at the same position. That this curve might reflect the activity of the one photoreceptor, presumably the cone, in spite of the close agreement with the absorption spectrum of the rod pigment, rhodopsin is dis-cussed in the paper. The results are also explained in terms of light adaptation to the environment where light of shorter wavelengths prevails.