Gustatory response of marbled rockfish Sebastiscus marmoratus was recorded from the facial nerve supplying the anterior palate. In amino acids, the lowest threshold was for L‐proline at 10−6–10−5 M; in ATP‐related substances, the value for inosine was approximately 10−5 M and in organic acids, the value for L‐lactic acid was approximately 10−6 M. An almost complete self‐adaptation was observed for stimulants after 5 s application. While a weak solution of L‐lactic acid as adapting stimulus depressed the response to it completely, it did not appreciably affect the response to 10‐times or more concentrated L‐lactic acid solution. In contrast to a weak solution, a moderate solution caused a severe depression of the response to stronger solutions, resulting in a shift of the dose–response curve towards a high concentration range. Time for recovery from adaptation differed depending on chemicals and stimulus duration: for 10−4 M L‐lactic acid, it took about 2.3 and 4.5 s for 1/2 recovery of response magnitude under unadapted condition from the adaptation after 1 s‐ and 5 s‐stimulation, respectively. L‐Lactic acid and L‐alanine strongly depressed the response to each other, yielding a rightward shift of the dose–response curve. A similar profound cross‐adaptation was also observed between inosine and 5′‐inosinic acid. The possible role of gustation is discussed.

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