Lecture 05 - Membrane Potentials and Sensation

Lecture 05 - Membrane Potentials and Sensation - Lecture 5...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 5 – Membrane Potentials and Sensory Systems Selected Members Of The Classes of Neurotransmitters (Table 9.1) Choline Derivative Biogenic Amines Amino Acids Neuropeptides Others Acetylcholine Catecholamines Dopamine Epinephrine Norepinephrine Serotonin Histamine Glutamate Asparate Glycine GABA TRH Vasopressin Oxytocin Substance P Endogenous opioids Enkephalins Endorphins Nitric oxide ATP 1. The same neurotransmitter can cause opposite responses depending on the environment it is in. 2. Acetylcholine a. Causes an EPSP in the brain b. Causes an IPSP in the heart 3. Amino Acids a. Glutamate (primary EPSP neurotransmitter), but Asparate causes same response b. GAMA (primary IPSP neurotransmitter), but Glycine causes same response 4. Tyrosine derivatives – found in nervous system; nerves extend from base of spinal cord up through the brain; modulate activities in the higher brain such as alertness, awakeness, consciousness, etc. a. Epinephrine b. Norepinephrine – creates an EPSP in the heart c. Dopamine 5. Histamine derivative a. Histamine – usually found in olfactory neurons 6. Tryptophan derivative a. Serotonin 7. Neuropeptides – first thought to be hormones a. TRH, Vasopressin, Oxytocin – most common neurotransmitter hormones b. Substance P – released from nerves for temperature and pain sensation (no hormone function) c. Opioids – alleviate pain by binding to morphine receptors 8. Some neuros release nitric oxide or even carbon monoxide. These are gaseous neurotransmitters, which can diffuse directly across the plasma membrane. So they do not bind to membrane receptors but instead bind to cytoplasmic receptors. Fast Synaptic Response – Ionotropic Receptor/Ion Channel (Fig 9.3a) 1. The neurotransmitter binds to an ion channel, causing it to open. 2. This causes the cell to be flooded with ions. 3. If the channel is for Na + /K + , Na + flows in and K + flows out, but overall it causes depolarization and an EPSP because more Na + enters than K + leaves. 4. If the channel is for Cl - , chloride flows in and causes an IPSP. 5. This response occurs within 5-15 milliseconds or even faster. It is the fastest of all responses. 6. There is no amplification in this process.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

Lecture 05 - Membrane Potentials and Sensation - Lecture 5...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online