Neurons, communication and transduction
Download as PPTX, PDF6 likes4,042 views
This document discusses neuronal anatomy, physiology, and communication. It covers the following key points: - Neurodevelopment continues throughout life, with synaptogenesis and myelination occurring after birth. Competitive elimination restructures the brain in adolescence. - Neurons synthesize proteins in different locations - peripheral proteins in the cytoplasm and integral/secretory proteins in the endoplasmic reticulum and Golgi apparatus. Some protein synthesis also occurs in dendrites. - Neurotransmission can occur through classic synaptic transmission, retrograde transmission from postsynaptic to presynaptic neurons, and volume transmission where neurotransmitters diffuse to distant sites without synapses. - Signal transduction refers to communication between presynaptic and posts
Neurons, communication and transduction
- 1. Neurons, Communication and Transduction Adapted from Steven Stahl MD, PHD
- 2. BASIC ANATHOMY AND PHYSIOLOGY
- 3. Anatomy and Physiology of The Neuron
- 4. Synaptic Neurotransmission and Neurodevelopment • Neurogenesis, neuronal selection and migration occur before birth. • Differentiation, myelination and synaptogenesis continue throughout entire life • Competitive elimination is a process of brain restructuring that occurs in adolescence.
- 6. Protein synthesis • Peripheral proteins (proteins who live in the cytoplasm) are made on free polysomes and transported into the axon and dendrites. • Integral or secretory proteins (proteins that are inserted into a membrane) are made on the rough endoplasmic reticulum, transported to the Golgi apparatus where they are packed into vesicles – ready for transport.
- 8. Synthesis of Membrane and Secretory Proteins
- 9. Some Protein Synthesis Occurs in The Dendrites
- 12. Retrograde Neurotransmission • The postsynaptic neuron can communicate with the presynaptic neuron (such is the case with endogenous canabinoids, NO and NGF).
- 13. Volume Neurotransmission • Neurotransmission can occur without a synapse(by diffusion of the neurotransmitter to sites that are distant from its own synapse).
- 14. Volume Neurotransmission of Dopamine in The Prefrontal Cortex • There are few dopamine reuptake pumps in the prefrontal cortex. The excess dopamine diffuses and finds receptors on other neurons.
- 15. Volume Neurotransmission to Autoreceptors on Monoamine Neurons • Autoreceptors are situated on the same neuron and cause inhibition of transmission. • For instance dopamine diffuses out of the synapse in the prefrontal cortex and stimulates the autoreceptors on the same neuron, thus inhibiting dopaminergic transmission.
- 18. Signal Transduction • Refers to communication between the genome of the presynaptic neuron and the genome of the postsynaptic neuron. • It can happen both ways: the genome of the postsynaptic neuron can also communicate back with the genome of the presynaptic neuron. • Signal transduction is a slow process taking hours or days.
- 19. Signal Transduction is a Two Way Street
- 20. Signal Transduction Cascade • The cascade of events that take place after the stimulation of the postsynaptic receptors. • The third messenger can be a KINASE which adds phosphate groups to proteins to create phosphoproteins. • The third messenger can also be a PHOSPHATASE which removes phosphate groups from phosphoproteins • The balance between kinases and phosphatases determines the downstrean chemical activity.
- 21. Four Types of Signal Transduction Cascade • G protein linked systems • Ion channel-linked systems • Hormone linked systems • Neurotrophin-linked systems Neurotransmitters activate G protein linked systems and ion channel linked systems. Both of these systems activate genes in the cell nucleus.
- 22. Signal Transduction Cascades • The G protein linked system works through a cascade involving cAMP and Protein kinase A. • The ion channel systems works through Calcium and calcium modulin kinase. Both of these systems activate genes in the cell nucleus by phosphorylating a protein there called CREB (cAMP response element-binding protein). • Certain hormones (like estrogen and steroids) enter the neuron, bind to their receptors in the cytoplasm, forming a hormone nuclear receptor complex. This complex enters the nucleus and interact with hormone response elements (HRE) to trigger activation of specific genes. • The neurotrophin system activates a series of kinase to trigger gene expression, which may control synaptogenesis and neuron survival. Ras is a G protein, Raf is a kinase, MAPK is mitogen activated protein kinase and GSK3 is glycogen synthase kinase 3.
- 23. Four Most Important Signal Transduction Cascades