Unit 2 Biopsychology - Psychopharmacology and Schizophrenia

Cocaine:

Catecholamine agonist, increases activity at both dopamine and norepinephrine synapses by blocking reuptake.

Benzodiazepines (diazepam/Valium, chlordiazepoxide/Librium):

GABA agonist that binds to the GABA-A ionotropic receptor at the benzodiazepine site. Increases GABA binding to another site.

Atropine (Atropa belladonna, Scopolamine/hyoscine or "Devil's Breath"):

Acetylcholine antagonist, blocks the muscarinic subtype of the acetylcholine receptor.

In the brain, Acetylcholine receptors are involved with:

Attention and memory

Alzheimer's disease is associated with reduced levels of:

The neurotransmitter acetylcholine (ACh)

Cholinesterase inhibitors (Donepezil & Aricept) prevent:

The enzyme ACh-esterase (AChE) from deactivating ACh. Disinhibition, or inhibiting the enzyme that deactivates ACh, facilitates ACh activity at the synapse.

Curare (Arrow Poison from Chondrondendron tomentosum and Strychnos toxifera plants):

Acetylcholine antagonist, blocks the nicotinic subtype of the acetylcholine receptor.

The nicotinic subtype of acetylcholine receptor is found at:

The neuromuscular junction.

Because the nicotinic subtype of the acetylcholine receptor is found at the neuromuscular junction, Curare causes:

Paralysis and often death due to paralysis of respiration.

Botox (Botulinum toxin):

Acetylcholine antagonist that blocks the release of acetylcholine at the neuromuscular junction.

Botox may have a strong application in:

Reducing wrinkles or inhibiting muscle spasms with local injections.

Chlorpromazine (Thorazine, Largactil):

Dopamine antagonist, first discovered receptor blocker, blocking D1 and D2 receptors equally.

Chlorpromazine was one of the first drugs used to treat:

Schizophrenia

Chlorpromazine is in the class of drugs known as:

Phenothiazines

Reserpine (Rauwolfia serpentina plant):

Dopamine antagonist, inhibits DA release by destroying the synaptic vesicles containing DA in the presynaptic button

Reserpine isn't used anymore because:

Lowers blood pressure to dangerous levels at therapeutic doses.

Phenothiazines (general use as a dye or anthelmintic):

(Chlorpromazine) Class of DA antagonist drugs that block D1 and D2 receptors equally.

Butyrophenones (haloperidol/Haldol, sprioperidol):

Class of DA antagonist drugs that block D2 receptors but not D1.

Butyrophenones are generally more effective than ______ at treating schizophrenia:

Phenothiazines

Neuroleptics:

Class of drugs used to treat schizophrenia by inhibiting dopamine receptors in the brain.

Clozapine

Atypical antischizophrenic drug, targets D1 receptors rather than D2. Given when traditional D2 neuroleptic therapy doesn't work.

Clozapine may have:

Fewer side effects.

Agonist drugs:

Activate receptors by binding to them. This causes a biological response similar to the body's natural substances.

Antagonist drugs:

Block receptors by binding to them. There is no activation. Prevents natural neurotransmitters or agonists from binding. Decrease/inhibit the biological response.

According to Pinel, chlorpromazine and reserpine are examples of a ____ drug:

Antagonist

According to Pinel, iproniazid and SSRIs (Prozac) are examples of a ___ drug:

Agonist

Cholinergic antagonists: mechanisms of action

Block the effects of acetylcholine (ACh) at the cholinergic receptor. The mechanism depends on which receptor they block.

Muscarinic antagonist mechanisms of action:

Completely blocks acetylcholine from binding to muscarinic acetylcholine receptors. Prevents activation of the parasympathetic nervous system.

Nicotinic antagonist mechanisms of action:

Block nicotinic receptors in autonomic ganglia, prevents ACh from activating both sympathetic and parasympathetic postganglionic neurons.

NMDA receptors:

Require both glutamate and a co-agonist (glycine, D-serine) to become activated, a process which is essential for synaptic plasticity.

Benzodiazepines affect GABA receptors by:

Acts as positive allosteric modulators on GABA-A receptors. Binds to a specific site on GABA-A receptors and enhances the effects of the inhibitory neurotransmitter GABA.

The effect of benzodiazepines on GABA receptors results in:

Enhanced neuronal inhibition, producing sedative, anticonvulsant, and muscle-relaxant effects.

Drugs affect the mechanisms of synaptic transmission by interfering with:

The synthesis and storage of neurotransmitters, their release into the synapse, postsynaptic receptor binding, and removal from the synapse.

What are the classes of neuroleptic drugs?

Phenothiazines (chlorpromazine), Butyrophenones (haloperidol).

Phenothiazines (chlorpromazine):

Bind both D1 and D2 receptors.

Butyrophenones (haloperidol):

Bind D2 receptors but not D1.