Thermally induced salivary secretion in anesthetized rats

  • Teruo Nakayama
  • Kazuyuki Kanosue
  • Hideto Tanaka
  • Tatsurou Kaminaga
Heart, Circulation, Respiration and Blood; Environmental and Exercise Physiology


Effect of thermal stimulation on salivary secretion was examined in urethane anesthetized (i.p., 1.0 g/kg) rats. First, rectal temperature (T re) was maintained at various levels by warming the whole trunk with a heating blanket. Copious salivary secretion occurred whenT re reached a threshold value above 40°C, which is considerably higher than the threshold for tail vasodilation. Local warming of the scrotum, face, or hypothalamus also elicited salivary secretion, but only ifT re was in a limited range just below the threshold temperature at whichT re alone would induce salivary secretion. The higher theT re within that limited range, the lower the temperature of the site locally warmed at which salivary secretion began. Changes in temperature of the abdomen, not including the scrotum, modulated the salivary secretion elicited by scrotal warming. Hypothalamic and scrotal temperatures interacted with each other to affect salivary secretion. Temperature signals from both core and periphery thus appear to be integrated in bringing about salivary secretion. Thermally induced salivary secretion may function as a basis for saliva spreading behavior observed in rats in a hot environment.

Key words

Salivary secretion Hyperthermia Scrotal temperature Abdominal temperature Facial temperature Hypothalamic temperature Rat 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Elmér M, Ohlin P (1970) Salivary glands of the rat in a hot environment. Acta Physiol Scand 79:129–132PubMedCrossRefGoogle Scholar
  2. Elmér M, Ohlin P (1971) Salivary secretion in the rat in a hot environment. Acta Physiol Scand 83:174–178PubMedCrossRefGoogle Scholar
  3. Furuyama F (1982) Strain difference in thermoregulation of rats surviving extreme heat. J Appl Physiol 52:410–415PubMedGoogle Scholar
  4. Hainsworth FR (1967) Saliva spreading, activity, and body temperature regulation in the rat. Am J Physiol 212:1288–1292PubMedGoogle Scholar
  5. Hainsworth FR, Stricker EM (1970) Salivary cooling by rats in the heat. In: Hardy JD, Gagge AP, Stolwijk AJ (eds) Physiological and behavioral temperature regulation. CC Thomas, Springfield, pp 611–626Google Scholar
  6. Hainsworth FR, Stricker EM (1971) Relationship between body temperature and salivary secretion by rats in the heat. J Physiol (Paris) 63:257–259Google Scholar
  7. Hales JRS, Hutchinson JCD (1971) Metabolic, respiratory and vasomotor responses to heating the scrotum of the ram. J Physiol (Lond) 212:353–375Google Scholar
  8. Hellon RF (1983) Central projections and processing of skin-temperature signals. J Therm Biol 8:7–8CrossRefGoogle Scholar
  9. Hubbard RW, Matthew CB, Francesconi R (1982) Heat-stressed rat: effects of atropine, desalivation, or restraint. J Appl Physiol 53:1171–1174PubMedGoogle Scholar
  10. Ingram DL, Legge KF (1972) The influence of deep body and skin temperatures on thermoregulatory responses to heating of the scrotum in pigs. J Physiol (Lond) 224:477–487Google Scholar
  11. Ishikawa Y, Nakayama T, Kanosue K, Matsumura K (1984) Activation of central warm-sensitive neurons and the tail vasomotor response in rats during brain and scrotal thermal stimulation. Pflügers Arch 400:222–227PubMedCrossRefGoogle Scholar
  12. Kanosue K, Nakayama T, Ishikawa Y, Hosono T (1984) Threshold temperatures of diencephalic neurons responding to scrotal warming. Pflügers Arch 400:418–423PubMedCrossRefGoogle Scholar
  13. Kanosue K, Nakayama T, Ishikawa Y, Hosono T, Kaminaga T, Shosaku A (1985) Responses of thalamic and hypothalamic neurons to scrotal warming in rats: nonspecific responses. Brain Res 328:207–213PubMedCrossRefGoogle Scholar
  14. Matsuo R, Kusano K (1984) Lateral hypothalamic modulation of the gustatory-salivary reflex in rats. J Neurosci 4:1208–1216PubMedGoogle Scholar
  15. Nakayama T (1985) Thermosensitive neurons in the brain. Jpn J Physiol 35:375–389PubMedCrossRefGoogle Scholar
  16. Paxinos G, Watson C (1982) The rat brain in stereotaxic coordinates. Academic Press, SydneyGoogle Scholar
  17. Roberts WW, Martin JR (1974) Peripheral thermoreceptor control of thermoregulatory responses of the rat. J Comp Physiol Psychol 87:1109–1118PubMedCrossRefGoogle Scholar
  18. Roberts WW, Martin JR (1977) Effects of lesions in central thermosensitive areas on thermoregulatory responses in rat. Physiol Behav 19:503–511PubMedCrossRefGoogle Scholar
  19. Roberts WW, Mooney RD (1974) Brain areas controlling thermoregulatory grooming, prone extension, locomotion, and tail vasodilation in rats. J Comp Physiol Psychol 86:470–480PubMedCrossRefGoogle Scholar
  20. Roberts WW, Mooney RD, Martin JR (1974) Thermoregulatory behaviors of laboratory rodents. J Comp Physiol Psychol 86:693–699PubMedCrossRefGoogle Scholar
  21. Schmidt I (1984) Interaction of behavioral and autonomic thermoregulation. In: Hales JRS (ed) Thermal physiology. Raven Press, New York, pp 309–318Google Scholar
  22. Stricker EM, Hainsworth FR (1971) Evaporative cooling in the rat: interaction with heat loss from the tail. Q J Exp Physiol 56:231–241PubMedGoogle Scholar
  23. Toth DM (1973) Temperature regulation and salivation following preoptic lesions in the rat. J Comp Physiol Psychol 82:480–488PubMedCrossRefGoogle Scholar
  24. Waites GMH (1961) Polypnoea evoked by heating the scrotum of the ram. Nature 190:172–173PubMedCrossRefGoogle Scholar
  25. Waites GMH (1962) The effect of heating the scrotum of the ram on respiration and body temperature. Q J Exp Physiol 47:314–323PubMedGoogle Scholar

Copyright information

© Springer-Verlag 1986

Authors and Affiliations

  • Teruo Nakayama
    • 1
  • Kazuyuki Kanosue
    • 1
  • Hideto Tanaka
    • 1
  • Tatsurou Kaminaga
    • 1
  1. 1.Department of PhysiologyOsaka University Medical SchoolKita-ku, OsakaJapan

Personalised recommendations