Secondary messengers

Question 1

Role of 2nd Messengers in Modulating Cellular Activity

Answer 1

2nd messengers are small signaling molecules that are produced in response to receptor activation and can modulate cellular activity. They include cyclic nucleotides, inositol phosphates, and calcium ions.

Question 2

Importance of Spatial and Temporal Localisation of 2nd Messengers for Signal Specificity

Answer 2

The spatial and temporal localization of 2nd messengers is crucial for signal specificity. This allows for precise control of cellular processes and prevents cross-talk between different signaling pathways.

Question 3

Association of 3 Major Receptor Classes with 2nd Messenger Function

Answer 3

G protein-coupled receptors (GPCRs)

Enzyme-linked receptors

Ion channel-coupled receptors

Question 4

Effector Enzymes Enabling Different Classes of Receptor to Couple to the Same Response

Answer 4

Different classes of receptors can couple to the same response via different effector enzymes. For example, both GPCRs and enzyme-linked receptors can activate phospholipase C (PLC), which in turn produces inositol phosphates as 2nd messengers.

Question 5

Examples of Different 2nd Messengers that Converge on a Common Target

Answer 5

Different 2nd messengers can converge on a common target, allowing for integration and amplification of signaling pathways. For example, both cyclic AMP (cAMP) and inositol triphosphate (IP3) can activate protein kinase A (PKA).

Question 6

Role of Glial Cell Neurotransmitter Reuptake with Particular Reference to the Glutamate Shuttle

Answer 6

Glial cells are responsible for removing neurotransmitters, such as glutamate, from the synaptic cleft via reuptake transporters. Glutamate is then converted into glutamine by glial cells, which is transported back to neurons to be converted back into glutamate via the glutamate shuttle.

Question 7

Role of Neurotransmitter Transporters in Non-Vesicular (Calcium-Independent) Neurotransmitter Release

Answer 7

Neurotransmitter transporters are responsible for regulating the levels of neurotransmitters in the synaptic cleft and can also contribute to non-vesicular (calcium-independent) neurotransmitter release.

Question 8

Mechanisms of Actions and Main Properties of Drugs Acting on Transporters

Answer 8

Drugs that act on transporters, such as tiagabine (GABA transporter inhibitor), fluoxetine (serotonin transporter inhibitor), cocaine (dopamine transporter inhibitor), and amphetamine (dopamine and norepinephrine transporter agonist), can have various mechanisms of action and properties. For example, cocaine blocks the reuptake of dopamine, leading to an increase in dopamine levels and a pleasurable feeling.