Excitation of striatal neurons by dexamphetamine is not abolished by either chloral hydrate or urethane anaesthesia

In order to understand differences between studies maintaining that dopamine actions are significantly reduced as a result of chloral hydrate anaesthesia or not affected to any appreciable extent, striatal neuronal responses to the indirect dopamine agonist, dexamphetamine, were examined in rats anaesthetized with either chloral hydrate (400 mg/kg) or urethane (1.5 g/kg). Striatal neuronal activity was markedly depressed by chloral hydrate and urethane. However, striatal neurons still responded to 2.5 mg/kg dexamphetamine with marked excitation. These results indirectly support earlier iontophoretic studies on the excitatory action of dopamine on striatal neurons in chloral hydrate-anaesthetized animals. Furthermore, the ability of dexamphetamine, primarily an indirect dopamine agonist, to excite striatal neurons in these anaesthetized animals suggests that stimulation of both D1 and D2 receptors is not abolished by anaesthesia.