Physiology & behavior
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Although starch is the world's most abundant nutritive carbohydrate, its sensory properties are not as well understood as those of sugars. Previous researchers have assumed that all starches have the same flavor. The present experiments examined flavor differences among starches. ⋯ Similar results were obtained with corn amylopectin and potato starch, even though these starches differ greatly with regard to the effects of cooking on preference in untrained rats. However, rats trained to avoid potato starch avoided this starch to a greater degree than did rats trained to avoid corn amylopectin; conversely, rats trained to avoid corn amylopectin avoided this starch to a greater degree than did rats trained to avoid potato starch. Therefore, the flavor of starch is complex; there are specific flavor notes related to species and cooking.(ABSTRACT TRUNCATED AT 250 WORDS)
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Physiology & behavior · Aug 1992
The influence of the stomach on crop function and feeding behavior in domestic turkeys.
We tested the hypotheses that motility of the crop and muscular stomach are coordinated and that the stomach exerts primary control over crop filling and emptying in domestic turkeys. Simultaneous recordings of motility of the crop, esophagus, and stomach with implanted strain gauge transducers and visual observations of food passage using image intensification radiography revealed an inverse relationship between the frequency of stomach and crop contractions. ⋯ Artificially filling the crop of fasted turkeys prior to the first morning meal did not decrease the amount of feeding activity or the total amount of food consumed during that meal. It is suggested that meal termination is associated with the degree of inhibition of esophageal peristalsis.
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Physiology & behavior · Mar 1992
Effect of medullary raphe lesions on sexual behavior in male rats with or without treatments of p-chlorophenylalanine.
Male sexual activities were tested in androgen-treated castrated male rats with lesions of the raphe obscurus nucleus (ROBL) or lesions of the raphe magnus nucleus (RMGL). The ROBL male rats showed low levels of mounting, intromission and ejaculation frequencies, and prolonged mount latencies compared to castrated and sham-operated control males. The sexual activity in the RMGL group was comparable to that of the controls. ⋯ This indicates that PCPA facilitates male sexual behavior. However, the suppressive effect of ROBL still remained even after deprivation of serotonin. Moreover, PCPA acts on serotonergic neurons other than those in the raphe obscurus nucleus, thereby facilitating mount activities.
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Physiology & behavior · Aug 1991
Rapid reentrainment of the circadian clock itself, but not the measurable activity rhythms to a new light-dark cycle in the rat.
Experiments were performed to determine if the circadian clock reentrains more quickly to an 8-hour phase shift in light-dark (LD) cycles than does the overt rhythm of activity. To investigate the reentrainment of the clock itself to an 8-hour advance or delay in the LD cycle, the rats were released into constant darkness only two or three days after a shift in LD cycle, and the amount of the phase shift of the clock itself was estimated from where free-running rhythm started by backward extrapolation. If the circadian clock could rapidly reset itself to the new LD cycle, it was predicted that the free-running rhythm of activity would start from near the dark period of the new LD cycle rather than the preceding one. ⋯ When rats (n = 24) were released into constant darkness two days after the LD cycle was advanced by 8 hours, 12 rats started the activity near time of dark period of the new LD cycle, while 9 rats started the activity near time of dark period of the preceding LD cycle. The remaining 3 rats showed the activity of the free-running rhythm near intermediate phase (transient phase). On the other hand, when the rats were not released into constant darkness after LD cycle was advanced by 8 hours, it took 6.4 days for activity rhythm to reentrain to the advanced LD cycle.(ABSTRACT TRUNCATED AT 250 WORDS)
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Physiology & behavior · Jan 1990
Influence of cold pain in the hand on skin impedance, heart rate and skin temperature.
Twenty-one healthy volunteers took part in the study, the aim of which was to determine the influence of acute pain on skin impedance, skin temperature and heart rate. Acute pain was induced by cold exposure. ⋯ The results show that changes in skin impedance as a result of acute pain can easily be recorded and could be a useful tool in monitoring acute pain. The technique is better than monitoring heart rate or skin temperature.