0.4- Angonist & antagonist

Flashcards covering agonists, antagonists, related neurotransmitters, and relevant studies.

Agonists and Antagonists

Substances that affect the function of neurotransmitters by either enhancing or inhibiting their effects at the synapse.

Acetylcholine

A neurotransmitter involved in learning, memory, and muscle movement; plays a critical role in encoding memories and is essential for muscle contraction.

Agonists

Chemicals or drugs that enhance or mimic the action of a neurotransmitter by binding to receptor sites on the postsynaptic neuron and activating them.

Endorphins

Painkillers; morphine is an agonist.

Nicotine

Binds to acetylcholine receptors, leading to increased alertness and attention; an agonist.

Synapse

The gap between neurons.

Neurotransmission

When the pre-synaptic neuron fires neurotransmitters like dopamine and serotonin across the synapse and they bind to the receptor sites on the post-synaptic neuron.

Endogenous Agonists

Agonists that occur naturally in the brain (e.g. serotonin).

Pramipexole

An agonist of dopamine receptor sites; may be an effective treatment for people with depression.

SSRIs

Selective serotonin reuptake inhibitors; increase the amount of serotonin that binds to receptor sites of neurons.

Anhedonia

Diminished interest or pleasure in response to stimuli that were previously perceived as rewarding.

Pramipexole

A dopamine agonist commonly prescribed for people with Parkinson's disease; may increase chances of addiction due to dopamine's association with pleasure and reward.

Aim of Olds and Milner (1954) Rat Study

To investigate how stimulation of specific brain regions influences behavior, particularly the brain's reward system.

Method of Olds and Milner (1954) Rat Study

Electrodes were implanted into the brains of rats, targeting areas suspected to be linked to reward, such as the nucleus accumbens or regions in the dopaminergic pathways. When rats pressed a lever, the electrodes would deliver electrical stimulation to these areas.

Findings of Olds and Milner (1954) Rat Study

The rats would compulsively press the lever repeatedly, sometimes thousands of times per hour, to receive stimulation. In some cases, they ignored food, water, and rest, continuing to press the lever until they collapsed or died from exhaustion.

Conclusion of Olds and Milner (1954) Rat Study

The study demonstrated the powerful influence of the brain's reward pathways, specifically those involving dopamine.

Aim of Cusin et al. (2013) study

Test the effectiveness of pramipexole for the treatment of MDD (Major Depressive Disorder).

Methods of Cusin et al. (2013) study

Was a randomized, double-blind, placebo-controlled study, where participants were randomly allocated to take either pramipexole or a placebo for 8 weeks. Depression symptoms were measured using the MADRS questionnaire (Montgomery-Asberg Depression Rating Scale).

Results of Cusin et al. (2013) study

Showed that there was a significant reduction in the MDD symptoms in the pramipexole group; the effects were modest.

Conclusion of Cusin et al. (2013) study

Could be a possible treatment for people with MDD who have not been successful with other frontline drugs (e.g. SSRIs).

Agonist

A chemical that amplifies the effect of a neurotransmitter by binding to the receptor sites of that neurotransmitter and activating them.

Antagonists

Block or inhibit the action of neurotransmitters by occupying receptor sites but not activating them.

Naloxone

An antagonist for opioid receptors, used to treat opioid overdoses.

Beta-blockers

Act as antagonists for norepinephrine and epinephrine (adrenaline), reducing symptoms of anxiety or high blood pressure.

Ketamine

An up and coming superstar in the world of drug therapy for MDD, because the neurotransmitter glutamate could be the key to understanding the origins of depression.

Glutamate

An excitatory neurotransmitter; ketamine is an antagonist of its receptor sites.

Aim of Lapidus et al. (2014) study

To test the safety and effectiveness of using ketamine to treat depression.

Methods of Lapidus et al. (2014) study

20 people with major depressive disorder were randomly allocated into one of two conditions. One group were given ketamine while the other was given a placebo (saline solution). The treatments were administered intranasally (up the nose). The effect this had on depression was measured using the Montgomery-Asberg Depression Rating Scale (MADRS) one day after the treatment.

Results of Lapidus et al. (2014) study

The ketamine group had a significant decrease in their depression symptoms after 24 hours. There were also no reported side-effects of the ketamine.

Conclusion of Lapidus et al. (2014) study

Ketamine could be a safe and effective way to treat depression. One of its major benefits is that it's fast acting (much faster than SSRI's).

Agonists and Antagonists

Substances that affect the function of neurotransmitters by either enhancing or inhibiting their effects at the synapse.

Agonists

Chemicals or drugs that enhance or mimic the action of a neurotransmitter by binding to receptor sites on the postsynaptic neuron and activating them.

Endogenous Agonists

Agonists that occur naturally in the brain (e.g. serotonin).

Agonist

A chemical that amplifies the effect of a neurotransmitter by binding to the receptor sites of that neurotransmitter and activating them.

Antagonists

Block or inhibit the action of neurotransmitters by occupying receptor sites but not activating them.

Naloxone

An antagonist for