The mechanisms for ketamine induced cardiovascular effects are complex and also Ketamine effect on blood pressure characteristics. Direct stimulation of the CNS leading to increased sympathetic nervous system outflow seems to be the most important mechanism for cardiovascular stimulation.
One of the characteristic of Ketamine is related to blood pressure and is therefore termed as Ketamine effect on blood pressure, is a dose-dependent inhibition of uptake of 3H-noradrenaline by both neuronal and extraneuronal processes was found during ketamine anesthesia which may account for the positive chronotropic and pressor effects of the drug.
Concomitant rise in noradrenaline and adrenaline concentrations occur due to ketamine, implying cardiovascular stimulant effect of ketamine is due to sympathoneuronal and sympatho adrenal activity, presumably brought about by a central mechanism of action of the drug.
Although, epinephrine levels are found significantly lower after isomer than racemic mixture, implying the increase in the haemodynamic parameters due mainly to norepinephrine.
Ketamine effect on blood pressure inhibits the brainstem parasympathetic cardiac neurons leading to decrease in parasympathetic cardiac activity and increase in heart rate.
Ketamine might attenuate cardiovascular responses such as baroreflex by interacting, at least in part, with the NMDA receptor in the nucleus tractus solitarius in the brain thus effecting the Blood pressure.