SUMMARY
1. Chronic ingestion of caffeine by male NIH strain mice alters the density of a variety of central receptors.
2. The density of cortical A1 adenosine receptors is increased by 20%, while the density of striatal A2A adenosine receptors is unaltered.
3. The densities of cortical β1 and cerebellar β2 adrenergic receptors are reduced by ca. 25%, while the densities of cortical α1 and α2 adrenergic receptors are not significantly altered. Densities of striatal D1 and D2 dopaminergic receptors are unaltered. The densities of cortical 5 HT1 and 5 HT2 serotonergic receptors are increased by 26–30%. Densities of cortical muscarinic and nicotinic receptors are increased by 40–50%. The density of cortical benzodiazepine-binding sites associated with GABAA receptors is increased by 65%, and the affinity appears slightly decreased. The density of cortical MK-801 sites associated with NMDA-glutaminergic receptors appear unaltered.
4. The density of cortical nitrendipine-binding sites associated with calcium channels is increased by 18%.
5. The results indicate that chronic ingestion of caffeine equivalent to about 100 mg/kg/day in mice causes a wide range of biochemical alterations in the central nervous system.
Keywords: caffeine, adenosine receptors, adrenergic receptors, cholinergic receptors, serotonin receptors, GABA receptors, calcium channels, dopamine receptors, NMDA receptors.
Comments