Where do neurotransmitters bind to elicit a postsynaptic response?

Where do neurotransmitters bind to elicit a postsynaptic response?

• A. Receptors on the postsynaptic cell
• B. Voltage-gated channels on the presynaptic membrane
• C. Myelin sheath
• D. Mitochondria

Answer: (A)

Neurotransmitters elicit a postsynaptic response by binding to receptors on the postsynaptic membrane. When a transmitter binds, the receptor changes shape and either opens a ligand-gated ion channel (ionotropic receptor) to let ions flow and create a rapid postsynaptic potential, or activates a second-messenger system (metabotropic receptor) that modulates ion channels indirectly for slower, longer-lasting effects. The outcome—depolarization or hyperpolarization—depends on the receptor type and the ions involved. Binding to voltage-gated channels on the presynaptic membrane is part of the release mechanism, not the postsynaptic binding that generates the response. The myelin sheath and mitochondria are not sites where neurotransmitters bind to create postsynaptic effects.

Neurotransmitters elicit a postsynaptic response by binding to receptors on the postsynaptic membrane. When a transmitter binds, the receptor changes shape and either opens a ligand-gated ion channel (ionotropic receptor) to let ions flow and create a rapid postsynaptic potential, or activates a second-messenger system (metabotropic receptor) that modulates ion channels indirectly for slower, longer-lasting effects. The outcome—depolarization or hyperpolarization—depends on the receptor type and the ions involved.

Binding to voltage-gated channels on the presynaptic membrane is part of the release mechanism, not the postsynaptic binding that generates the response. The myelin sheath and mitochondria are not sites where neurotransmitters bind to create postsynaptic effects.