Using your knowledge of neurotransmitters, suggest how general anaesthetics may exert their effect.

GABA is the main inhibitory neurotransmitter in the brain - it prevents action potentials from being generated. GABA opens chloride channels in membrane to allow chloride ions to move into the ICF down the concentration gradient. This makes the interior of the cell more negative-in other words the cell is hyperpolarised and the likelihood of generating action potentials decreases. Many general anaesthetics interact with GABA to hyperpolarize the membrane and decrease the transmission of action potentials in the brain. Glutamate is the main excitatory neurotransmitter in the brain. It opens sodium and calcium channels to depolarise the cell. Some general anaesthetics block glutamate receptors making it more difficult to excite cells.