Biological Membranes and Neuronal Signaling Flashcards

Vocabulary flashcards covering key concepts from membrane biology, GPCR signaling, action potential kinetics, and synaptic transmission.

Phosphatidylcholine (PC)

The chemical constituent that directly provides biological membranes with their characteristic polar and nonpolar bilayer arrangement.

Integral Membrane Proteins

The key class of proteins that regulate solute transport functions across biological membrane bilayers.

Active Transport

The type of solute transport that requires energy input to move a solute uphill against a concentration gradient.

K+ Ion Influx Response

The rapid response that restores a neuron's cell membrane potential back to the resting potential of $-70\,\text{mV}$ following a $10\,\text{mV}$ hyperpolarization to $-80\,\text{mV}$.

Solute Transport Work (Neurons)

A critical neuronal function directly linked to the ion gradients generated by the $\text{Na}^+/\text{K}^+\text{-ATPase}$.

NMDARs

Glutamate ionotropic receptors that serve as a $\text{Ca}^{2+}$ ion channel when a neuron's membrane is depolarized and $\text{Mg}^{2+}$ ions are removed from the ion conduction pore.

GPCR G-Protein Activation

The mechanism by which activated, ligand-bound G protein-coupled receptors (GPCRs) transmit signals to G proteins by promoting the exchange of GDP for GTP.

Adenylate Cyclase

A GPCR pathway component utilized when a receptor signals via increasing cAMP levels.

Store-Operated Ca2+ (SOC) Activation Signal

The depletion of endoplasmic reticulum (ER) $\text{Ca}^{2+}$ levels, which signals the activation of $\text{Ca}^{2+}$ influx via store-operated $\text{Ca}^{2+}$ channels.

Gi Pathway

The G protein-activated pathway coupled to both the $\alpha_2$ adrenergic and the $\text{M}_2$ muscarinic GPCRs.

β-Arrestin

A protein in the GPCR pathway with dual functions, serving as a mediator of receptor desensitization and as a scaffold protein for initiating G protein-independent signaling pathways.

Biased Agonism

A GPCR signaling mechanism where the receptor preferentially activates G protein pathways relative to the $\beta\text{-Arrestin}$ pathway.

Tyrosine Kinase Receptor (TKR) Transduction Sequence

The sequential order of TKR signal transduction: TKR autophosphorylation $\rightarrow$ adaptor protein $\rightarrow$ GEF $\rightarrow$ Ras $\rightarrow$ Raf $\rightarrow$ MEK $\rightarrow$ MAPK.

Axon Depolarization Response at +20 mV

The dual response initiated by rapid axon membrane depolarization to $+20\,\text{mV}$ via $\text{Na}_\text{V}$ channel activation, resulting in both $\text{Na}_\text{V}$ channel inactivation and $\text{K}_\text{V}$ channel opening.

Relative Refractory Period

The state of an axon membrane produced by roughly a $10\,\text{mV}$ hyperpolarization due to the slow closing of $\text{K}_\text{V}$ channels.

Synaptotagmin

The protein that acts as the $\text{Ca}^{2+}$ sensor of the SNARE complex, allowing synaptic vesicle trafficking and docking to the synaptic terminal membrane.

Direct Excitatory Neurotransmitters

Neurotransmitters, specifically Acetylcholine and Glutamate, that act as direct excitatory signals by stimulating neuron membrane depolarization.

Voltage-Gated Ca2+ Channels

Key ion channels in the synaptic terminal activated by an action potential to stimulate neurotransmitter secretion.

Saltatory Action Potential Conduction

A mode of rapid action potential conduction characterized by a high degree of myelination along the axon fiber.

Long-Term Potentiation (LTP)

A form of postsynaptic modulation associated with increased glutamate sensitivity due to increased expression of AMPA receptor ion channels.