Neurotransmitters

Question 1

what are the criteria that was established to categorize neurotransmitters

Answer 1

1. chemicals must be present in the presynaptic terminal
2. chemical must be released in amounts suffience to effect a response in the postsynaptic cell
3. when added to extracellular fluid, the chemical should induce the same changes as the endogenous chemical
4. a mechanism for breakdown/removal should exist
5. effects of drugs on transmission at the synapse must be similar for both endogenous and exogenous apllication

Question 2

how to differienate the two types of neurotransmitters

Answer 2

1. small
   - main neurotransmitters
   - most synapes in the CNS
   - small clear vesicles
   - low-freq stimulation
   - reuptake or specific enzymes
2. large
   - uncommmon
   - co-transmitters with the small neurotransmitters
   - neuropeptides at nucleus or ER
   - large dense-corded vesicles
   - high-freq stimulation (need more Ca2+ influx)
   - extracellular peptidases ( no reuptake, gets taken into blood)

Question 3

Describe Acetylcholine

Answer 3

• nicotinic receptors are neruomusclar (ionotropic and excitatory)
• muscarinic receptors, metabotropic and inhibitory on heart
• implicated in attention and cognitive processes
• seen with a decrease in the number of cholingeric neurons in the basal forebrain seen in Alzgeimer’s Disease

Question 4

Describe Glutamate

Answer 4

• most common neurotransmitter in brain
• lots of receptor subtypes
• important for learning and memory
• mainly excitatory and ionotropic
• mGlu1-8 is metabotropic and either excitatory or inhibitatory

Question 5

Describe GABA

Answer 5

• ommon inhibitory neurotransmitter in brain
• except in development (such as aduitory recptors) it can be excitatory
• 20% of cortical neurons are GABAergic
• related to anxiety - modulated by benzodiazepines and barbiturates

Question 6

describe catecholamines

Answer 6

• dopamine, noreponephrine, epinephrine
• all start with tyrosine
• involved in arousal, aggresion, motivation pleasure and reward
• movemnt
• schizophreniz

Question 7

describe serotonin

Answer 7

• amine
• neuromodulator- co-localized with glutamate or GABA
• involved in mood, sleep, appetite and sexual function
• SSRIs - selective serotonergic reuptake inhibitors

Question 8

describe endorphins

Answer 8

• opiate, metabotropic, generally inhibitory
• pain; stimulation=analegesia
• runners high

Question 9

neuropeptide y

Answer 9

• most common peptide neurotransmitter in brain
• abunat in hypothalamus
• cell grwth, food intake
• alcoholism. anxiolutic

Question 10

substance P

Answer 10

• cell growth, vomiting, pain