Final answer:
The statement is false; alcohol and general anesthetics can act on both synaptic and extrasynaptic receptors affecting ion channels and altering neuronal activity.
Step-by-step explanation:
The statement that alcohol and general anesthetics can only act on extrasynaptic receptors is false. These substances can indeed act on various receptor types, including both extrasynaptic and synaptic receptors. Synaptic receptors are located at synapses, which are the points of communication between neurons, while extrasynaptic receptors are found outside of these traditional synaptic contact points.
Alcohol and general anesthetics are known to affect ion channels that include both synaptic and extrasynaptic receptors, thereby altering neuronal activity and resulting in their sedative and anesthetic effects.