Glossary of (pp8)neurotransmitters

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Effects of GABA
Implicated in Huntington's Chorea
-abnormalities in GABA secreating neurons result in epilepsy
-inhibitory transmitter substance with wide spread distribution throughout the brain and spinal cord.
2 types of Ach receptors?
1) Nicotinic
2) Muscarinic
Ionotropic Receptors?
Receptors that are asscoiated with the ligand activated ion channels
Serotonin is what type of neurochemical?
Effects of Norepinephrine
Involved in the control of alertness/wakefulness
-found in neurons in the ANS and in the brain
NE neurons in the brain produce inhibitory postsynaptic potentials
-NE neurons outside the NS usually have an excitatory effect.
Effects of Serotonin
Usually produces an inhibitory affect. Implicated in mood, eating behavior, sleep, agressive behavior & pain regulation.
Effects of Glutamic Acid (Glutamate)
Believed to be 1st neurotransmitter to evolve
-excitatory and inhibitory affects on axons, raising or lowering threshold of excitation thus affectrate at which action potentials occur
-principle excitatory transmitter in the brain
-brain contains several types of glutamate receptors, most of them metabotrophic and control sodium channels
3 types of catecholamines:
1) dopamine
2) epinephrine
3) norepinephrine
Parkinson's Disease
Degenerative loss of body mov'nt capacities, due in part to the loss of neurons in the substantia nigra (in the basil ganglia) & corresponding loss of Dopamine.
How many different types of neurotransmitters exist?
There are approx. 60 different types of neurotransmitters.
What is a ligand?
A molecule that binds to another molecule
-neurotransmitters are the ligands of their receptors
Effects of dopamine
-can be inhibitory or excitatory depending on the nature of post-synaptic membrane.
-found in the substantia nigra. Degeneration of DA neurons in this area results in Parkinson's disease.
-Involved in movement, att'n, addiction, learning & possibly schizophrenia.
Degnerative loss of cognitive capacity resulting in part due to a deficit in acetycholine (Ach).
Effects of Epinephrine
Also called adrenalin
-transmitter in the CNS
-Produced by adrenal medulla & released into blood stream to enhance arousal.
Biochemical hypothesis that schiz symptoms such as hallucinations may be casued by an excess of dopamine.
What happens to neurotransmitters after they have been used?
recycling - after neurotransmitters have been used, they are recycled by the body for later use. They are broken down by enzymes so that they vacate the receptor sites, and then brought back to the axon terminal and stored.
Metabotropic Receptors
Receptors that are associated with signal proteins & G-proteins
-more prevalent that ionotrophic receptors
-effects slower to develop; longer lasting & more diffuse than ionotropic receptors.
Acetycholine acts on what three sites?
1)Neuromuscular junction
2)Autonomic NS
Glycine Effects?
Inhibitory transmitter found in spinal cord & lower portions of the brain
-normally inhibit activity of motor neurons.
Describe the transmission of neurotransmitters.
When the synaptic cleft is too large to be jumped, the gap can be crossed using neurotransmitters located in sacs within the axon terminal (the end of the axon). The sac with the appropriate neurotransmitters is forced through the membrane into the cleft, releasing the neurotransmitters into the cleft. Neurotransmitters then make their way to receptor sites on the post-synaptic neuron, where they stimulate the neuron and the action potential begins again.
Types of Amino-Acid Neurotransmitters.
Glutamic Acid
What are the Blocking Agents of Ach (nicotinic)?
1) d-turbo curarine
2) succinyl choline
->blocks muscle activity
What are the Blocking Agents of Ach (muscarinic)?
->blocks ANS activity

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