1.2 Amine Neurotransmitters

Briski

what was the first NT identified

ACh

ACh activates which receptors

nicotinic and muscarinic

ACh activates receptors in which nervous system(s)

CNS and PNS

most cholinergic neurons reside in the ____ but some occur in the ____

subcortical areas; cerebral cortex

explain the synthesis of ACh

Acetyl CoA + Choline —> ACh + CoA (enzyme: Choline Acetyltransferase)

is the synthesis of ACh reversible or irreversible

irreversible

muscarinic receptors are ____ while nicotinic receptors are ____

GPCRs; ionotropic

what are the muscarinic receptor subtypes

M1-M5

what are the functional roles of cholinergic neurons in the CNS

memory, motivation, perception, cognition, attention, and fine motor functions

what are some examples of monoamine neurotransmitters

dopamine, norepinephrine, and epinephrine

what are the methods of inactivation for monoamine neurotransmitters

reuptake, metabolism, and drifting

explain how to make the main three catecholamines

which enzymes are responsible for the metabolism of catecholamine monoamine neurotransmitters

MAO and COMT

what are the subtypes of the MAO receptor

MAOa and MAOb

MAOa is responsible for metabolizing which catecholamines (monoamine NTs)

NE, EPI, and 5HT

MAOb is responsible for metabolizing which catecholamines (monoamine NTs)

DA

COMT is responsible for metabolizing which catecholamines (monoamine NTs)

DA, NE, EPI

dopamine receptor subtypes

D1-D5

catecholamine receptors are _____

GPCRs

Catecholamine receptor subtypes can induce…

postsynaptic membrane depolarization or hyperpolarization

the nigrostriatal pathway is an example of a ____ pathway

CNS dopamine

explain the nigrostriatal pathway

substantia nigra dopaminergic neurons project to the caudate nucleus-putamen (extrapyramidal system)

degeneration of the nigrostriatal pathway is associated with which disease

parkinsons

degeneration of the ____ pathway is associated with parkinsons disease

nigrostriatal

the mesolimbic forebrain system is an example of a(n) _____ pathway

CNS dopamine

explain the mesolimbic forebrain system

midbrain ventral tegmentum dopamine neurons project to the limbic system

the mesolimbic forebrain system is associated with…

emotional behavior and schizophrenia

which CNS Dopamine pathway is associated with emotional behavior and schizophrenia?

mesolimbic forebrain system

the mesocortical pathway is an example of a(n) ____ pathway

CNS dopamine

explain the mesocortical pathway

midbrain dopamine neurons project to cerebral cortex

the mesocortical pathway is associated with…

logical reasoning, perception

the _____ pathway is associated with logical reasoning and perception

mesocrotical

dysfunction associated with the mesocortical pathway is associated with…

psychosis

dysfunction in the ____ pathway is associated with psychosis

mesocoritcal

the tuberoinfundibular system is an example of a _____ pathway

CNS dopamine

explain the tuberoinfundibular system

hypothalamic arcuate nucleus dopamine neurons terminate in the median eminence and release the neurotransmitter for vascular transport to the anterior pituitary gland

which area of the CNS has the highest concentration of EPI

brainstem

NE neuronal cell bodies are located in the…via…

brainstem locus coeruleus project rostra via the medial forebrain bundle

explain the synthesis of 5HT(serotonin)

how many 5HT receptors are GPCRs

12

5HT receptors elicit which types of responses (IPSP or EPSP)

both!

what are the 5HT receptor subtypes

5HT1_a-f

5HT2_a-c

5HT3

5HT4

5HT5

5HT6

5HT7

how is 5HT inactivated

MAOa metabolizes 5HT to form 5HIA which is then metabolized to 5HIAA OR it can be reuptaked to the presynaptic terminal

which enzyme is responsible for inactivating serotonin

MAOa

where do 5HT neurons reside in the CNS

midline region of the upper brainstem/pons; raphe nuclei

5HT1 is coupled to…

inhibitory G proteions

5HT2, 5HT4, 5HT6, and 5HT7 are all coupled to…

stimulatory (excitatory) G proteins

5HT3 receptors are linked to…

ion channels (ionotropic)

other amine neurotransmitters include

octopamine

tyramine

melatonin

histamine

posterior hypothalamic histamine neurons are associated with…

body temp regulation , vascular dynamics, retinal arousal

posterior hypothalamic _____ neurons are associated with body temp regulation , vascular dynamics, retinal arousal

histamine

histamine receptors are which type of receptors

GPCRs

what are the histamine receptor subtypes

H1-H4

H1 receptors location

glial cells, blood vessels

H1 receptor function

mobilize Ca

H1 receptor antagonists (antihistamines) cause…

sedation

where are H2 receptors located

nerve cells

H2 receptor function

stimulates adenyl cyclase and increases cAMP

most H2 antagonists do not…

cross the BBB

H2 antagonists are used as…

antacids (due to their role in gastric acid secretion)

H3 receptor function

nerve cell calcium influx

where are H4 receptors found

hematopoietic cells (mast cells, WBCs, and dendritic cells)

H4 receptor antagonists lead to

alertness

how do peptide NT’s differ from classical NT’s

synthesis takes place on ribosomes in the cell bodies and is directed by mRNA

neuropeptide transmitter examples

orexin, opioids, gastrin etc

orexin is also called

hypocretin

what are the Orexin receptor subtypes

OX1 and OX2

OX1 and OX2 are which type of receptor

GPCRs

Orexin receptors are involved in…

activating monoamine and ACh neurons to maintain awake state and energy, balance, and metabolism

lack of oxrexin produces which disease

narcolepsy

narcolepsy is caused by…

lack of orexin

true or false:

many neurotransmitters coexist in neurons and can be released at the same time into the synapse

true

what are some atypical neurotransmitters

CO, NO, purines (adenosine and ATP), cannabinoids

why are atypical neurotransmitters hella weird

not usually stored in the synaptic vesicles or released via exocytosis

purine receptor classes

P1 and P2

P1 receptors bind to…

adenosine receptors

what are the adenosine receptors

A1 and A2

A1 antagonists act as…

cognition enhancers

A1 ____ act as cognition enhancers

antagonists

example of an A1 antagonist

caffiene

caffeine is an example of an…

A1 antagonist

caffeine acts as a ___ at low doses but at high doses it acts as a ____

stimulant ; irritant

A2 receptors have an inverse relationship with _____

dopamine

A2 receptors have an _____ relationship with dopamine

inverse

A2 antagonists have potential to be used as…

anti-parkinsons agents

P2 receptors bind to…

ATP

P2 receptors that bind to ATP are involved in…

pain perception, inflammation

P2 antagonists may be effective in treating…

chronic pain

_____ receptor antagonists may be effective in treating chronic pain

P2

what are the cannabinoids

anandamide and 2-arachidonylglycerol

cannabinoid receptors

CB1 and CB2

the cannabinoid receptors are which type of receptor

GPCR

cannabinoid receptor agonists are used for

stimulation of appetite in anorexic, HIV, and cancer patients

chronic pain relief

depression

cannabinoid receptor antagonists can potentially treat

nausea, vomiting, and obesity

how is NO (nitric oxide) made

nitric oxide synthase (NOS)

excessive NO can be ______

neurotoxic

how can NO excess be neurotoxic

contributes to neural damage caused by stroke

CO is highly toxic at ____ concentrations

high

CO may play a role in

circadian rhythm