Selective activation of CCK-B receptors does not induce sleep and does not affect EEG slow-wave activity and brain temperature in rats.
Systemic injections of cholecystokinin octapeptide sulfate ester (CCK-8-SE) elicit various behavioral and autonomic responses, such as increases in nonrapid-eye-movement sleep (NREMS) and hypothermia. There are two CCK receptors; both CCK-A and CCK-B receptors are stimulated by CCK-8-SE. The relative importance of the CCK-A and CCK-B receptors in the somnogenic and hypothermic effects of CCK-8-SE is not well understood. In the present experiments, we studied the effects of the selective activation of CCK-B receptors by CCK tetrapeptide (CCK-4) or nonsulfated CCK-8 (CCK-8-NS) on sleep and brain temperature (Tbr). Rats were injected intraperitoneally with saline on the control day and with CCK-8-NS (10, 50, or 250 microg/kg) or CCK-4 (10, 50, or 250 microg/kg) on the test day 5-10 min before dark onset. Electroencephalogram, electromyogram, and Tbr were recorded for 12 h. None of the treatments affected sleep or Tbr significantly, with the exception of 10 microg/kg CCK-4, which transiently decreased the amount of NREMS, and 10 microg/kg CCK-8-NS, which slightly increased REMS. These results suggest that the activation of CCK-B receptors by systemic injection of CCK-4 or CCK-8-NS is not sufficient to elicit increased NREMS and hypothermia in rats.
Chang
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Department of Biological Sciences, Fordham University, Bronx, NY 10458, USA.
Kapás
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D000818:Animals; D001143:Arousal / Q000187:drug effects / Q000502:physiology; D001341:Autonomic Nervous System / Q000187:drug effects / Q000502:physiology; D001833:Body Temperature Regulation / Q000187:drug effects / Q000502:physiology*; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects; D008297:Male; D017286:Polysomnography; D051381:Rats; D017207:Rats, Sprague-Dawley; D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin / Q000187:drug effects / Q000502:physiology*; D012844:Sincalide / Q000494:pharmacology; D012894:Sleep Stages / Q000187:drug effects / Q000502:physiology*; D012895:Sleep, REM / Q000187:drug effects / Q000502:physiology; D013758:Tetragastrin / Q000494:pharmacology
D043887:Receptor, Cholecystokinin B; D011949:Receptors, Cholecystokinin; D013758:Tetragastrin; D012844:Sincalide