Thirst-Reducing Effects of Water by Stomach Fistula vs. Water by Mouth Measured by Both a Consummatory and an Instrumental Response
Evidence that drinking in a variety of species of mammals is regulated by both oral-pharyngeal and by gastrointestinal mechanisms has been secured in studies by E. P. Adolph, J. P. Barker, and P. Hoy, R. T. Bellows, and E. J. Towbin. Since all these studies have used a single measure, the amount of water consumed, it is conceivable that the effects are specific to drinking reflexes and do not have more general effects on learned behavior instrumental to securing water. These more general effects are normally associated with the drive of thirst. In short, there is evidence that mechanisms regulating drinking occur in at least three places: mouth-throat, stomach-intestine, and hypothalamus. Both the instrumental and the consummatory measures yielded the same pattern of results, namely, water injected directly into the stomach produced a decrement and water taken normally by mouth produced a greater decrement.