OBJECTIVE: The anesthetic ketamine has been reported to cause both an increase of the plasma histamine concentration, notably in cats, and a cardiovascular depression. The latter has been described in humans and in other species. However the relevance of the histamine fluctuation for the ketamine-induced hemodynamic changes has not been determined. SUBJECTS AND TREATMENT: We studied the contribution of histamine to the hemodynamic effects induced by IV ketamine (7 mg/kg) in 12 sevoflurane anesthetized cats, of which half had been pre-treated with combined H(1)- and H(2) -receptor antagonists. METHODS: The mean arterial pressure (MAP) and the heart rate (HR) from both untreated (group C) and pre-treated (group AH) cats were recorded before and after the ketamine administration. The plasma histamine concentration was also measured. RESULTS: Plasma histamine fluctuations in the control and the antihistamine-treated group followed a similar pattern (no statistical differences); an initial rise that peaked 2 min after ketamine injection (from 0.63 +/- 0.11 ng/ml to 2.22 +/- 0.69 ng/ml in the C group, and from 0.71 +/- 0.10 ng/ml to 1.09 +/- 0.28 ng/ml in the AH group) followed by an immediate decrease in plasma concentrations. As for the hemodynamic variables under analysis, in the control group ketamine administration was followed by an early 30.3 +/- 8.1% reduction (p < 0.005) in the MAP with no associated changes in the HR. In the antihistamine pre-treated group, ketamine caused a further decrease of the MAP (41.7 +/- 2.3%), and a significant (p < 0.01) 11.6 +/- 2.9% reduction of the HR. CONCLUSION: Ketamine in anesthetized cats triggers histamine release and induces cardiovascular depression. The depression is more pronounced under the blockade of histamine activity through histamine receptor antagonists.
OBJECTIVE: The anesthetic ketamine has been reported to cause both an increase of the plasma histamine concentration, notably in cats, and a cardiovascular depression. The latter has been described in humans and in other species. However the relevance of the histamine fluctuation for the ketamine-induced hemodynamic changes has not been determined. SUBJECTS AND TREATMENT: We studied the contribution of histamine to the hemodynamic effects induced by IV ketamine (7 mg/kg) in 12 sevoflurane anesthetized cats, of which half had been pre-treated with combined H(1)- and H(2) -receptor antagonists. METHODS: The mean arterial pressure (MAP) and the heart rate (HR) from both untreated (group C) and pre-treated (group AH) cats were recorded before and after the ketamine administration. The plasma histamine concentration was also measured. RESULTS: Plasma histamine fluctuations in the control and the antihistamine-treated group followed a similar pattern (no statistical differences); an initial rise that peaked 2 min after ketamine injection (from 0.63 +/- 0.11 ng/ml to 2.22 +/- 0.69 ng/ml in the C group, and from 0.71 +/- 0.10 ng/ml to 1.09 +/- 0.28 ng/ml in the AH group) followed by an immediate decrease in plasma concentrations. As for the hemodynamic variables under analysis, in the control group ketamine administration was followed by an early 30.3 +/- 8.1% reduction (p < 0.005) in the MAP with no associated changes in the HR. In the antihistamine pre-treated group, ketamine caused a further decrease of the MAP (41.7 +/- 2.3%), and a significant (p < 0.01) 11.6 +/- 2.9% reduction of the HR. CONCLUSION:Ketamine in anesthetized cats triggers histamine release and induces cardiovascular depression. The depression is more pronounced under the blockade of histamine activity through histamine receptor antagonists.
Authors: U Gergs; J Weisgut; K Griethe; N Mißlinger; U Kirchhefer; Joachim Neumann Journal: Naunyn Schmiedebergs Arch Pharmacol Date: 2021-06-24 Impact factor: 3.000