Astrocyte Signaling and Brain Function

These flashcards cover the physiological properties, signaling mechanisms, and functional roles of astrocytes as discussed in the lecture transcript.

How does the resting membrane potential (RMP) of an astrocyte compare to that of a neuron?

The RMP of an astrocyte is approximately $-80\,mV$, which is more negative than the RMP of a neuron, typically around $-70\,mV$.

According to the lecture, what is the membrane resistance of astrocytic membranes?

Astrocytic membranes have a very low membrane resistance of less than $10\,M\Omega$.

Which specific transporters are mentioned for the astrocytic uptake of GABA and Glutamate to terminate neurotransmission?

GABA is taken up by GAT1 and GAT3 transporters, while Glutamate is taken up by the EAAT (glutamate transporter).

What structures compose the gap junctions that allow astrocytes to form a syncytium for $K^+$ buffering?

Gap junctions are composed of connexons, which are each made of 6 connexins.

What is the primary difference in duration between an astrocytic $Ca^{2+}$ transient and a neuronal action potential?

An astrocytic $Ca^{2+}$ transient lasts for seconds, whereas a neuronal action potential typically lasts for milliseconds.

What biochemical pathway triggers the release of $Ca^{2+}$ from the Endoplasmic Reticulum (ER) in astrocytes?

The Phospholipase C (PLC)/inositol 1,4,5-trisphosphate ($IP_3$) pathway, which leads to the activation of $IP_3$ receptors ($IP_3R$) on the ER.

In the control of brain vascular tone, which astrocyte-derived substances act as vasodilators and which act as vasoconstrictors?

Vasodilators include $PGE_2$ (prostaglandin E2) and EET (epoxyeicosatrienoic acid), while 20-HETE (hydroxyeicosatetraenoic acid) acts as a vasoconstrictor.

What are the three components involved in a "tripartite synapse"?

The presynaptic terminal, the postsynaptic terminal, and the astrocyte process.

Which three molecules are specifically identified as gliotransmitters released by astrocytes to signal to neurons?

Glutamate, ATP/ADO (Adenosine), and D-Serine.

What does the acronym DREADD stand for, and what synthetic ligand does it respond to?

DREADD stands for Designer Receptor Exclusively Activated by Designer Drugs, and it responds to the synthetic ligand clozapine N-oxide (CNO).