Projection neurons in the cortex and hippocampus: differential effects of chronic khat and ethanol exposure in adult male rats

BACKGROUND

Recent evidence suggests that many individuals who chew khat recreationally also drink ethanol to offset the stimulating effect of khat. The objective of this study was to describe the separate and interactive effects of chronic ethanol and khat exposure on key projection neurons in the cortex and hippocampus of young adult male rats.

METHODS

Young adult male Sprague Dawley rats were divided into six treatment groups: 2 g/kg khat, 4 g/kg khat, 4 g/kg ethanol, combined khat and ethanol (4 g/kg each), a normal saline control, and an untreated group. Treatments were administered orally for 28 continuous days; brains were then harvested, sectioned, and routine hematoxylin-eosin staining was done. Following photomicrography, ImageJ® software captured data regarding neuron number and size.

RESULTS

No differences occurred in counts of both granular and pyramidal projection neurons in the motor cortex and all four subfields of the hippocampal formation. Khat dose-dependently increased pyramidal neuron size in the motor cortex and the CA3 region, but had different effects on granular neuron size in the dentate gyrus and the motor cortex. Mean pyramidal neuron size for the ethanol-only treatment was larger than that for the 2 g/kg khat group, and the saline control group, in CA3 and in the motor cortex. Concomitant khat and ethanol increased granular neuron size in the motor cortex, compared to the 2 g/kg khat group, the 4 g/kg khat group, and the 4 g/kg ethanol group. In the CA3 region, the 4 g/kg ethanol group showed a larger mean pyramidal neuron size than the combined khat and ethanol group.

CONCLUSION

These results suggest that concomitant khat and ethanol exposure changes granular and pyramidal projection neuron sizes differentially in the motor cortex and hippocampus, compared to the effects of chronic exposure to these two drugs separately.

Chronic khat (Catha edulis) and alcohol marginally alter complete blood counts, clinical chemistry, and testosterone in male rats

INTRODUCTION

Khat (Catha edulis) is a recreational psychoactive drug with psychostimulant properties. While the use of this drug is widespread in eastern Africa, including the Horn of Africa, surveys and anecdotal data show that its use has become cosmopolitan, with users now living in Europe and North America as well. Recent data in Uganda suggest an increasing pattern of simultaneous khat and ethanol use particularly among young adults. However, the effects of this pattern of use remain largely unknown, even though long-term use of either drug alone is known to be harmful. The aim of this study was to examine the toxic effects of simultaneous chronic administration of khat and ethanol on hematological parameters, clinical chemistry, and testosterone in a rat model.

METHODS

Adult male Sprague-Dawley rats were randomly assigned to one of six dose groups: 2 g/kg khat; 4 g/kg khat; 4 g/kg ethanol; combined khat and ethanol (4 g/kg each); control; and an untreated group. Treatments were given by gavage twice daily for 28 days, followed by determination of hematological parameters, blood clinical chemistry, and testosterone.

RESULTS

Ethanol alone significantly reduced platelet counts compared to control-, untreated and low-dose khat-treated rats; conversely low-dose khat significantly increased both the hemoglobin and hematocrit values, while ethanol alone also significantly increased the hemoglobin value compared to controls. Simultaneous khat and ethanol administration per se did not produce more toxic consequences in chronic use than either drug alone.

CONCLUSION

Chronic short-term khat use and ethanol dependence individually produce note-worthy effects on the blood, but not on clinical chemistry or testosterone. Chronic short-term combined khat and ethanol use does not produce more toxic effects compared to use of either drug alone. This provides an opportunity for appropriate clinical interventions to avert the chronic long-term effects that result from use of these drugs of abuse.