Effect of sub-chronic cocaine and lidocaine exposure on the lymphoid tissues in neonatal rats

Immunomodulation by cocaine and ketamine in postnatal rats

The abuse of cocaine (COC) in combination with ketamine (KET) among pregnant women was shown to be high. Transplacental exposure is not the only route by which a newborn may be exposed to these agents, but they can also distribute into breast milk. Chronic COC exposure is associated with immunological modulation in human and animal models. The effect of sub-chronic exposure to COC and KET alone and in combination on the developing immune system was assessed in neonatal male Sprague-Dawley (SD) rats. To simulate the route of exposure during lactation, newborn male rats were treated orally with saline, COC alone (20 mg/kg), KET alone (50 mg/kg), or KET (50 mg/kg) followed 15 min later by COC (20 mg/kg) from days 1 to 21 of life. Pups were sacrificed 30 min following the last treatment. Total circulating leukocyte and lymphocyte counts were decreased with relative neutrophilia, while spleen/body weight ratio and IgM antibody response to sheep red blood cells (SRBCs) were increased in animals treated with COC. Moreover, treatment with COC alone increased serum interleukin 10 (IL-10) concentration; however, it did not affect serum interferon gamma (IFN-gamma) concentration. On the other hand, KET treatment did not produce any significant change of any of these parameters. However, when co-administered with COC, the immunomodulatory effects of COC were prevented. COC caused a significant increase in serum corticosterone concentration that KET effectively prevented. Lack of significant change of plasma and tissue concentrations of norcocaine (NC) suggested no role for COC metabolism in COC-induced immunomodulation. However, the results of this study indicate that COC-induced immunomodulatory reactions and their prevention by KET most likely occurred through neuroendocrinal mechanisms.

Reduction of tissue concentration of cocaine in rat by ketamine

The coabuse of cocaine and ketamine occurs with high frequency. The presence of another active substance with cocaine allows for the potential of various drug-drug interactions to occur. This study investigated the tissue distribution after the administration of cocaine or ketamine alone and their combination in rat. Cocaine (5 mg/kg iv), ketamine (100 mg/kg by gavage), or ketamine followed by cocaine (same doses and routes of administration) was utilized. Tissue contents of cocaine and norcocaine were significantly lowered at 5, 15, and 30 min following ketamine administration versus cocaine alone. However, tissue contents of benzoylecgonine were significantly higher in the combination group compared to cocaine alone. On the other hand, cocaine administration did not affect the tissue disposition of ketamine. The results suggest that ketamine decreased cocaine tissue content, which may affect its pharmacological and toxicological profiles.