Antipsychotic Drugs - Dr. M Casely-Hayford Objectives 1

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What is the primary neurotransmitter implicated in psychotic behaviors such as schizophrenia?

Serotonin

Acetylcholine

Endorphins

Dopamine (correct)

What is the primary function of dopamine in the synapse?

Enhances neuronal firing

Promotes serotonin release

Regulates acetylcholine levels

Inhibits neuronal firing (correct)

Which class of antipsychotic drugs is associated with less extrapyramidal side effects?

Atypical (correct)

Typical

Antidepressants

Anxiolytics

What is the neurotransmitter primarily targeted by many antipsychotic drugs?

Dopamine Signup and view all the answers

Which neurotransmitter system, other than dopamine, is mentioned to be involved in the action of antipsychotic agents?

Serotonin Signup and view all the answers

What is the term used to refer to side effects like tremors and anxiety that are less common with atypical antipsychotic drugs?

Extrapyramidal side effects (EPS) Signup and view all the answers

What is the Chlorpromazine Index (CI) used for in the context of the text?

To determine the optimal position of X on the phenyl ring Signup and view all the answers

Why do phenothiazines need to have a 3-carbon chain between position 10 and the amino nitrogen for antipsychotic activity?

To promote proper receptor attachment Signup and view all the answers

Which substitution on the ring in phenothiazines lacks antipsychotic efficacy?

-H at position 2 Signup and view all the answers

How does the Z isomer differ from the E isomer in thioxanthene compounds?

The Z isomer has a better 3-D structure to fit the receptor site Signup and view all the answers

What does maintaining an effective size of the tertiary amino group on the side sidechain help achieve?

Activity enhancement by chain extension Signup and view all the answers

Why do thiothexene compounds display properties similar to piperazine sub-group of phenothiazines?

As they share similar pharmacological properties with phenothiazines Signup and view all the answers

What is the main mechanism of action for phenothiazines as antipsychotic drugs?

Acting as dopamine D2 receptor antagonists Signup and view all the answers

How does the two carbon distance between the anionic site and the ring site in receptor binding of phenothiazines occur?

Through molecular bending of the side chain Signup and view all the answers

What is the function of X, the electron withdrawing group in ring 'A' of phenothiazines?

Enhances binding to an electron rich area on the receptor Signup and view all the answers

What does the Chlorpromazine Index (CI) indicate in terms of potency?

CI greater than 1 indicates more potency than chlorpromazine Signup and view all the answers

Why does substitution at C1 have a deleterious effect on antipsychotic activity?

It prevents molecular bending Signup and view all the answers

Which pharmacophoric group of norepinephrine interacts with the receptor similarly to phenothiazines?

$CO_2^-$ group Signup and view all the answers

In receptor binding, what is the role of the sulfur atom at position 5 in phenothiazines?

Enhances receptor binding similar to a hydroxyl group in dopamine Signup and view all the answers

How do electron withdrawing groups affect phenothiazine activity?

$\delta+$ charge on 'A' ring increases binding to electron-rich areas on receptors Signup and view all the answers

Why is more than one substitution on the ring system detrimental to phenothiazine potency?

$\pi$-electron cloud gets disrupted Signup and view all the answers

'The side chain in phenothiazines creates a two carbon distance between which sites in receptor binding?'

'A' ring and nitrogen site Signup and view all the answers