TY - JOUR
T1 - Hypersensitivity of morphine-tolerant rabbits to the respiratory stimulant effect of a cholinergic agonist
AU - Weinstock, M.
AU - Dalith, M.
AU - Shohami, E.
PY - 1983
Y1 - 1983
N2 - The effect of morphine and oxotremorine, a centrally acting cholinergic agonist on the respiratory rate and arterial blood gases, was studied in rabbits given saline, increasing doses of morphine (5 mg/kg, 2 days; 10 mg/kg, 2 days; and 20 mg/kg, 3 days) injected at 12-hr intervals for 1 week. Care was taken to ensure that the chronically morphine-treated rabbits were neither under the influence of a previous dose of morphine nor in a phase of withdrawal when the response to test doses was measured. Tolerance to the respiratory depressant effect of morphine was demonstrated by the finding that a 5 times greater dose of morphine was needed to decrease respiration rate and raise arteriolar pCO2 than that given to saline-treated rabbits. The respiratory stimulant effect of oxotremorine, as demonstrated by an increase in respiration rate and decrease in Pa(Co)2, was significantly greater in morphine-tolerant rabbits. It is concluded that chronic opiate treatment can induce supersensitivity of the cholinergic systems subserving control of respiration.
AB - The effect of morphine and oxotremorine, a centrally acting cholinergic agonist on the respiratory rate and arterial blood gases, was studied in rabbits given saline, increasing doses of morphine (5 mg/kg, 2 days; 10 mg/kg, 2 days; and 20 mg/kg, 3 days) injected at 12-hr intervals for 1 week. Care was taken to ensure that the chronically morphine-treated rabbits were neither under the influence of a previous dose of morphine nor in a phase of withdrawal when the response to test doses was measured. Tolerance to the respiratory depressant effect of morphine was demonstrated by the finding that a 5 times greater dose of morphine was needed to decrease respiration rate and raise arteriolar pCO2 than that given to saline-treated rabbits. The respiratory stimulant effect of oxotremorine, as demonstrated by an increase in respiration rate and decrease in Pa(Co)2, was significantly greater in morphine-tolerant rabbits. It is concluded that chronic opiate treatment can induce supersensitivity of the cholinergic systems subserving control of respiration.
UR - http://www.scopus.com/inward/record.url?scp=0020512534&partnerID=8YFLogxK
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C2 - 6408245
AN - SCOPUS:0020512534
SN - 0022-3565
VL - 226
SP - 232
EP - 237
JO - Journal of Pharmacology and Experimental Therapeutics
JF - Journal of Pharmacology and Experimental Therapeutics
IS - 1
ER -