Anesthetic Drug Lidocaine Research Articles

Effects of dibenzepine and imipramine on the isolated rat heart

The tricyclic antidepressants, imipramine and dibenzapine and the local anaesthetic drug lidocaine were added to the recirculating perfusate in a rat heart perfusion apparatus. Each drug produced the following effects: (a) A dose-dependent decrease in impulse generation and impulse conduction velocity. (b) A dose-dependent decrease in cardiac contractile force. (c) A dose-dependent decrease in coronary flow preceded by an increase at lower concentrations. (d) A dose-dependent decrease in potassium loss from the heart. (e) Potentiation of the imipramine-induced decrease in contractile force and coronary flow in the presence of lidocaine. Further, in the concentration range in wich the antidepressants produced their cardiac effects, they stabilized eryhrocytes against hypotonic lysis. The antidepressants and the local anaesthetic share this effect and the cardiac effects with a variety of drugs commonly referred to as membrane stabilizers. It is concluded that the membrane stabilizers probably change the properties of biomembranes in a common way, and that the cardiac effects are secondary to these changes.

Cardiac effects of antiparkinson drugs, local anesthetics, and tranquilizers

The antiparkinson drugs, etybenztropine, prophenamine and benzhexole, the local anesthetic drug lidocaine, and the tranquilizing drug chlorpromazine were added to the recirculating medium in a rat heart perfusion apparatus. All the drugs caused the following effects: (a) A dose-dependent decrease in impulse generation and impulse conducting velocity. (b) A dose-dependent decrease in cardiac contractility. (c) A dose-dependent decrease in coronary flow preceded by an increase at lower concentrations. (d) A dose-dependent decrease in potassium loss from the hearts, followed by an increase at higher concentrations. An additive effect of chlorpromazine and etybenztropine on cardiac contractility was found. It is concluded that the changes in ECG cardiac contractility and coronary flow in the isolated perfused rat heart induced by antiparkinson drugs and local anesthetics are similar to those produced by tranquilizing phenothiazine derivatives. It is further suggested that the effects can be explained as secondary to a decrease in cell membrane permeability.