Neurotransmitters

Neurotransmitters videos

Neurotransmitters 100+ substances are known or suspected neurotransmitters Neurotransmitters affect the postsynaptic neurons as long as it remains bound to receptors Removal is essential for normal synaptic function

Neurotransmitters, cont. NTs may be EXCITATORY – stimulate the brain INHIBITORY – calm the brain

Neurotransmitters, cont. Neurotransmitters are removed in four ways 1. NTs diffuse away from synaptic cleft 2. Some NTs are destroyed by enzymes 3. Active transport into the releasing (presynaptic) neuron REUPTAKE 4. Active transport into neighboring neuroglia UPTAKE

Acetylcholine (Ach) One of the best studied NTs Released in both PNS & CNS Ach may be excitatory at some synapses (like the NMJ) Ach may also be inhibitory at some synapses Ach video

CNS Neurotransmitters INHIBITORY: GABA Glycine EXCITATORY: Glutamate Aspartate These four are also amino acids Some drugs, such as Valium, Ativan, Xanax and other benzodiazepines, increase the action of GABA, for anti-anxiety, sedative, anti-seizure results

Modified Amino Acids Norepinephrine (NE) Dopamine Arousal (waking from sleep), dreaming, regulating mood Dopamine Emotional responses, addictive behaviors, and pleasurable experiences Regulate skeletal muscle tone and some aspects of movement Schizophrenia is linked to excess dopamine

Drugs & NTs Cocaine produces euphoria by blocking the reuptake of dopamine Other drugs interact with receptors involved in the endorphine system

Parkinson’s Disease Degenerative disorder of the CNS Mainly affects the motor system Death of dopamine-generating cells Early symptoms: shaking, slowness of movement, difficulty walking Later symptoms: thinking, dementia Most cases occur after the age of 50 Michael J Fox, Mohammad Ali

Seratonin Sensory perception, temperature regulation, control of mood, appetite, and onset of sleep Relaxation & sleepiness SSRIs Selective Seratonin reuptake inhibitors Example: Prozac Block the reuptake of serotonin Prolongs the activity of serotonin Provides relief for those suffering from some forms of depression NT Serotonin is made from tryptophan (turkey) – concentration low in protein rich meal – unlikely to actually make us feel sleepy. However, carb-rich foods result in release of serotonin in brain – making us sleepy & relaxed

Endorphins Endorphins are neuropeptides Neuropeptides are aminoacids linked by peptide bonds Endorphins are the body’s natural painkillers

Frog heart physiology vid