Synaptic transmission

Definition

Synaptic transmission is the process by which one neuron communicates with another neuron across a synapse through the release of neurotransmitters. This critical mechanism allows for the transfer of signals within the nervous system, enabling the coordination of bodily functions and responses to stimuli.

5 Must Know Facts For Your Next Test

1. Synaptic transmission involves both electrical and chemical signaling, starting with an action potential traveling down the axon and ending with neurotransmitter release at the synapse.
2. There are two main types of synaptic transmission: excitatory, which increases the likelihood of an action potential in the receiving neuron, and inhibitory, which decreases this likelihood.
3. The efficiency of synaptic transmission can be modulated by various factors, including the presence of drugs, changes in receptor sensitivity, and alterations in neurotransmitter availability.
4. Calcium ions play a crucial role in synaptic transmission, as their influx into the presynaptic terminal is essential for triggering neurotransmitter release.
5. Reuptake mechanisms and enzymatic degradation help terminate synaptic transmission, ensuring that signals are not perpetually active and allowing for precise control of neuronal communication.

Review Questions

• How do neurotransmitters influence synaptic transmission and what role do they play in signal propagation between neurons?
  • Neurotransmitters are key players in synaptic transmission as they are released from presynaptic neurons into the synaptic cleft upon action potential arrival. They bind to specific receptors on postsynaptic neurons, resulting in either excitatory or inhibitory effects. This binding can lead to changes in membrane potential, which may trigger a new action potential in the receiving neuron, thus propagating the signal through the nervous system.
• Discuss the importance of calcium ions in the process of synaptic transmission and how they affect neurotransmitter release.
  • Calcium ions are essential for synaptic transmission because their influx into the presynaptic terminal is what triggers the vesicles containing neurotransmitters to fuse with the membrane and release their contents into the synaptic cleft. This process is often referred to as calcium-dependent exocytosis. Without calcium, neurotransmitter release would not occur effectively, leading to disrupted communication between neurons.
• Evaluate how modulation of synaptic transmission can impact neurological disorders and therapeutic approaches to treatment.
  • Modulation of synaptic transmission can significantly influence various neurological disorders by altering the balance between excitatory and inhibitory signaling in the brain. For instance, conditions like depression may involve deficits in excitatory neurotransmitter function, while epilepsy may arise from excessive excitatory activity. Therapeutic approaches often aim to restore balance by targeting specific receptors or neurotransmitter systems, such as using selective serotonin reuptake inhibitors (SSRIs) for depression or anticonvulsants for epilepsy, highlighting the importance of understanding synaptic transmission in clinical settings.

Related terms

Neurotransmitter: A chemical substance that transmits signals across a synapse from one neuron to another, influencing the activity of the receiving neuron.

Action potential: A rapid change in the membrane potential of a neuron that propagates along its axon, triggering the release of neurotransmitters at the synapse.

Receptor: A protein molecule located on the surface of a neuron that binds to specific neurotransmitters, initiating a cellular response.