Cholecystokinin and morphine-induced hypothermia

Area of Science:

• Neuroscience
• Pharmacology
• Endocrinology

Background:

• Choleystokinin (CCK) is a peptide hormone with diverse physiological roles.
• CCK and its analogs are known to influence thermoregulation.
• The specific receptor mechanisms underlying CCK-induced hypothermia require further elucidation.

Purpose of the Study:

• To investigate the effects of various CCK receptor agonists and morphine on core body temperature in mice.
• To determine the involvement of CCK(A) and CCK(B) receptors, as well as opioid receptors, in mediating hypothermic responses.

Main Methods:

• Subcutaneous administration of different doses of CCK-8 sulfate, CCK-8 unsulfate, CCK-4, caerulein, and morphine to mice.
• Utilized selective CCK(A) receptor antagonist MK-329 and CCK(B) receptor antagonist L-365,260.
• Administered opioid antagonist naloxone to assess opioid receptor involvement.

Main Results:

• Caerulein, CCK-8, and morphine induced dose-dependent hypothermia.
• CCK-8U and CCK-4 did not affect body temperature.
• MK-329 attenuated caerulein-induced hypothermia, while naloxone reduced morphine-induced hypothermia.
• Combined administration of morphine and caerulein resulted in enhanced hypothermia.
• MK-329 decreased the hypothermic response to the drug combination.

Conclusions:

• CCK(A) receptor activation is implicated in the hypothermic effects of CCK agonists and potentially morphine.
• Opioid receptors do not appear to mediate the hypothermic effects of CCK receptor agonists.
• CCK(A) receptor antagonism can mitigate hypothermia induced by CCK agonists and combined drug administration.