Question

The neurotransmitter selected is Dopamine.

PART 1: Nervous System Homeostasis Neurotransmitters are responsible for communication between neurons to ensure that cognition is maintained; the body is able to instantaneously maintain homeostasis to a threat; or store sensory input for later retrieval (form memories). These chemicals do this by providing a stimulus to either open ion channels that lead to depolarization (excitatory) or hyperpolarization (inhibitory) so as to allow the nervous system to perform the function it is required to do in order to maintain homeostasis. Many things we consume as pharmaceuticals (drugs), dietary supplements and even "nutrients" have impacts on neurological functions, thus exhibiting psychodynamic effects. Select a drug of your choice and examine the effects of the drug on the function of the neurotransmitter that have picked. Based on your selection, develop a well-formatted response no more than 700 words) that indicates: • The type of molecule classification is used to describe the neurotransmitter and what kind of effect the neurotransmitter has on the tissues it interacts with Indicating the type of molecule (use the table in the packet or information from PubChem) Describing is it excitatory or inhibitory • How the drug, dietary supplement or nutrient impacts the action of the neurotransmitter. Describing and explaining the means by which impact occurs (competitive inhibition, agonistic effect, antagonistic effect) and the mechanism by which responses are affected (receptor inhibition, receptor excitation, agonist or mimic behavior, antagonistic behavior) • The effect of the drug, dietary supplement or nutrient on nervous function. o Indicate how the drug impacts the normal functions and homeostasis for the person, or the means by which the drug acts within the normal feedback loop involving the neurotransmitter • Does use of the drug, dietary supplement or nutrient lead to reliance and dependency for normal functions O Reliance is based on the need for physiological functions to be normal, dependency is based on psychological responses that lead to the drive to consume and utilize. Where each is based on positive or negative adaptations at the receptor making where either more or less of the drug is necessary to obtain the same response as the initial exposure. And what happens when it is used too often, or if the person stops using it

Answer 1

1. A dopamine molecule consists of a catechol structure (a benzene ring with two hydroxyl side groups) with one amine group attached via an ethyl chain. As such, dopamine is the simplest possible catecholamine, a family that also includes the neurotransmitters norepinephrine and epinephrine.   

Dopamine functions as both an inhibitory and excitatory neurotransmitter depending upon where in the brain and at which particular receptor site it binds to. Adequate dopamine levels are needed to allow us to focus our attention in the moment and attend to matters at hand.

2. drugs like nicotine, L-dopa(mimic) ,bromantane acts as agonists by increasing the dopamine release by mechanisim of receptor excitation.Anti-psychotics decrease the dopamine levels by blocking the receptors -antagonistic activity. Supplements that acts as agonists for dopamine levels by agonistic  mechanism are green tea , avacado,fish etc.Melatonin manganese, lithium supplemets decrease dopamine levels by receptor inhibition .

3. When the neuron releases dopamine, it will bind to the postsynaptic dopamine receptor as well as the pre synaptic auto receptor. Binding of dopamine to the auto receptor inhibits the neuron from releasing more dopamine, i.e a negative feedback loop. If you have an antagonist selective for the auto receptor that doesn't bind to the postsynaptic receptors you inhibit the negative feedback loop thus amplifying dopamine transmission. This would be very roughly similar to blocking the dopamine transporter.

On the other hand if you have a "plain" dopamine antagonist, it will prevent the released dopamine from binding to the postsynaptic receptors, thus disrupting the signal. So the effect can actually be the opposite depending on which receptor (pre/post) you antagonize.

4.For suppose a man who is taking nicotine which is usually present in smoke ,it releases dopamine . if this person is addicted to it then the problem arises. On withdrawal he suffers withdrawal symptoms anxiety, depression, irritation etc. So a person when actually addicted to it on stopping it suffers psychic symptoms more than physiological symptoms.