What are chemical messengers released into the cleft?

What are chemical messengers released into the cleft?

• A. Hormones
• B. Neurotransmitters
• C. Enzymes
• D. Neuropeptides

Answer: (B)

Neurotransmitters are the chemical messengers released into the synaptic cleft to relay signals between neurons. When an action potential arrives at the presynaptic terminal, these molecules are released from vesicles into the tiny gap, diffuse across it, and bind to receptors on the postsynaptic membrane. This binding can create excitatory or inhibitory responses, depending on the transmitter and receptors involved, quickly influencing whether the next neuron fires. Hormones, by contrast, are released into the bloodstream to affect distant targets, not a nearby synapse. Enzymes are biological catalysts and aren’t the signaling molecules that cross the synaptic gap. Neuropeptides can act as signaling molecules in some contexts, but the standard term for messengers released into the cleft in rapid synaptic transmission is neurotransmitters.

Neurotransmitters are the chemical messengers released into the synaptic cleft to relay signals between neurons. When an action potential arrives at the presynaptic terminal, these molecules are released from vesicles into the tiny gap, diffuse across it, and bind to receptors on the postsynaptic membrane. This binding can create excitatory or inhibitory responses, depending on the transmitter and receptors involved, quickly influencing whether the next neuron fires.

Hormones, by contrast, are released into the bloodstream to affect distant targets, not a nearby synapse. Enzymes are biological catalysts and aren’t the signaling molecules that cross the synaptic gap. Neuropeptides can act as signaling molecules in some contexts, but the standard term for messengers released into the cleft in rapid synaptic transmission is neurotransmitters.