Final answer:
Receptor molecules in synapses are specific to certain neurotransmitters and bind to them transiently to transmit neural signals. This process is essential for neural communication, where neurotransmitters can activate or inhibit postsynaptic neurons through the opening of ion channels. A. tend to concentrate on presynaptic terminals.
Step-by-step explanation:
The role of receptor molecules in synapses is crucial for the transmission of signals between neurons. Receptor molecules are found on the postsynaptic membrane and they have a high degree of specificity for their respective neurotransmitters. This specificity can be likened to a key and lock mechanism, where only a specific neurotransmitter (key) can bind to its corresponding receptor (lock). The binding between a neurotransmitter and its receptor is not permanent but rather a specific chemical event. As such, the neurotransmitter does not bind irreversibly to the receptor, nor can it bind to receptors intended for other types of neurotransmitters.
Upon binding, certain neurotransmitters can trigger the opening of ligand-gated ion channels, leading to either excitatory or inhibitory effects on the postsynaptic neuron. For instance, the neurotransmitter acetylcholine causes postsynaptic Na+ channels to open and induces an excitatory postsynaptic potential, while GABA opening Cl- channels results in an inhibitory postsynaptic potential. After the signal is transmitted, neurotransmitters are either quickly degraded or reabsorbed by the presynaptic neuron, preparing the synapse for the next signal transmission.