Which neurotransmitters produce IPSPs?
Multiple select question.
Glycine
Aspartate
GABA
Glutamate
The correct answer and explanation is:
The correct answers are Glycine and GABA.
Explanation:
Neurotransmitters are chemicals that transmit signals across synapses in the nervous system. Depending on their effects on the postsynaptic neuron, neurotransmitters can cause excitatory or inhibitory postsynaptic potentials (EPSPs or IPSPs). IPSPs decrease the likelihood of an action potential being triggered in the postsynaptic neuron, typically by hyperpolarizing the membrane.
- GABA (Gamma-Aminobutyric Acid):
GABA is the primary inhibitory neurotransmitter in the central nervous system (CNS). When GABA binds to its receptors, it opens chloride ion channels, allowing Cl⁻ ions to flow into the postsynaptic neuron. This influx of negatively charged chloride ions causes the membrane potential to become more negative (hyperpolarized), which makes it more difficult for the neuron to reach the threshold required for an action potential. This is a classic example of an IPSP. - Glycine:
Glycine is another major inhibitory neurotransmitter, primarily found in the spinal cord and brainstem. Like GABA, glycine works by opening chloride ion channels. The influx of chloride ions also hyperpolarizes the neuron, producing an IPSP. Glycine is particularly important for regulating motor control and inhibiting excessive neural activity. - Glutamate:
Glutamate is the most common excitatory neurotransmitter in the brain. It typically binds to receptors that allow sodium (Na⁺) and calcium (Ca²⁺) ions to enter the postsynaptic neuron, causing depolarization and the production of an EPSP. Therefore, glutamate does not produce IPSPs but instead promotes neuronal excitation. - Aspartate:
Aspartate is another excitatory neurotransmitter, similar to glutamate. It activates receptors that allow positive ions like sodium to flow into the neuron, causing depolarization and generating EPSPs. Aspartate, like glutamate, does not produce IPSPs.
Thus, GABA and glycine are the neurotransmitters responsible for producing IPSPs, while glutamate and aspartate produce EPSPs.