We think you have liked this presentation. If you wish to download it, please recommend it to your friends in any social system. Share buttons are a little bit lower. Thank you!
Presentation is loading. Please wait.
Published byHannah Pruitt
Modified over 4 years ago
L'alfabeto degli odori
L’alfabeto degli odoriAnna Menini Neurobiology Sector International School for Advanced Studies Trieste, Italy
Common Odor Compounds alkanes Halides aldehydes amine alcoholsformiates X O H alcohols C carboxylic acids R aldehydes ketones esters OR alkanes X C N cyanide S H thiol 2 amine B r Halides
What is a transduction process?A transduction process is how the energy of an external stimulus is converted into an electrical signal
Sensory cells convert a stimulus into an electrical response by a process known as SENSORY TRANSDUCTION
How many mechanisms of transduction?Na Ca2+ 1- IONOTROPIC 2- METABOTROPIC molecules Light Na+ Ca2+ l R G C
Receptor potential= Generator potentialThe change in membrane potential produced by the stimulus is a graded potential and can be: positive or depolarizing negative or hyperpolarizing
Sensory receptor cellsSome sensory receptor cells have axons and generate action potentials Other cells do not generate action potentials
Scanning electron micrograph of theolfactory epithelium E. Morrison and R. Costanzo
1mm Morrison and Costanzo 1990
Olfactory transduction takes place in the cilia
How many odorant receptor genes?
Nobel Prize in Physiology or Medicine 2004Linda Buck Richard Axel “for their discoveries of odorant receptors and the organization of the olfactory system”
350 recettori 1000 recettori
How many type of odorant receptor per cell?1 type only
Randomly in each of four zonesHow are odorant receptors spatially expressed in the olfactory epithelium? Randomly in each of four zones
How many odorant molecules can activate an olfactory sensory neuron ?One neuron can respond to many odorant molecules
One type of odorant molecule: how many types of odorant receptors can activate?One type of odorant molecule can activate many types of odorant receptors
Denis A N D I P U F P O D R A B U P A N U B N C I A P B N O C D U G I
From olfactory epithelium to olfactory bulbRepresentation of olfactory information
Zonal Organization in the Olfactory SystemMori et al., 1999
Un certo odore attiva una definita combinazione di glomeruli
Information coding in the olfactory cortex
Epithelium Bulb Cortex
NASO BULBO CORTECCIA
Olfactory transduction cAMP is the main second messenger
Ca concentration increases in the cilia and has a dual effect 1- excitatory 2- inhibitory
Ca excitatory effect: direct activation of Cl current In situ Cl gradient measurements (rat, mucus/knob concentrations) [Cl-]i = 69 mM [Cl-]o = 55 mM Ecl = +6mV (Reuter et al.)
Adaptation Adaptation adjusts the dynamic range of the response to allow the sensory cell to respond to changes in odor concentration over a wide range.
Mechanism of adaptationIntracellular Calcium concentration controls adaptation acting on the transduction cascade
Transduction in an olfactory sensory neuron
Caged compound Uncaged: physiologically active
8-Bromo-cAMP 1- is resistant to hydrolysis by PDE2- activates cAMP-gated channels with higher affinity than cAMP
Transduction in an olfactory sensory neuron
Collaborators Japan Takashi Kurahashi Germany Benjamin Kaupp USAStuart Firestein Peter Mombaerts C.N.R. Genova Cristiana Picco Paola Gavazzo S.I.S.S.A. Trieste Laura Lagostena Anna Boccaccio Andrea Mazzatenta Giulietta Pinato Simone Pifferi Ranken Shimazaki
1 Chapter 52 Molecular Basis of Olfaction and Taste Copyright © 2012, American Society for Neurochemistry. Published by Elsevier Inc. All rights reserved.
Neural Signaling: Postsynaptic Potentials Lesson 9.
Taste. circumvallate papilla labelled lines There are five recognised modalities: sweet, sour, bitter, salt & umami. All mature taste bud cells have.
Mean = 75.1 sd = 12.4 range =
Physiology Behrouz Mahmoudi Olfactory System 1.
Lecture 12: olfaction: the insect antennal lobe References: H C Mulvad, thesis ( Ch 2http://
Receptors & Signaling. Assumed Knowledge Structure of membrane proteins Ion concentrations across membranes Second messengers in signal transduction Regulation.
LECTURE 18: OLFACTION AND TASTE REQUIRED READING: Kandel text, Chapter 32 Smell and Taste are the chemical senses Smell (olfaction) is the discriminating.
The sense of smell Outline Main Olfactory System Odor Detection Odor Coding Accessory Olfactory System Pheromone Detection Pheromone Coding 1.
Slide 1 Smell Olfaction brings both good news and bad news Pheromones Smell— a mode of communication as well as of detecting environment Important signals.
Olfact = To smell Olfaction detects chemicals in solution which is detected in the Olfactory Epithelium which is a yellow-tinged patch located in.
Types of Ion Channels Leak channels
Neurophysiology. The Resting Membrane Potential Intracellular (soma) Extracellular VV -70 mV.
Bioelectricity Provides basis for “irritability” or “excitability Fundamental property of all living cells Related to minute differences in the electrical.
Today –Sensory receptors General properties –Skin receptors.
بسم اللة الرحمن الرحيم Muscle and neuron as excitable tissue.
Local Potential (“Passive” Depolarization) Depolarization to Threshold depolarization produced by the stimulusdepolarization produced by the stimulus chemical,
Neurophysiology Opposite electrical charges attract each other
Part Fundamentals of Physiology Part II Food, Energy, and Temperature Part III Integrating systems Part IV Movement and Muscle Part V Oxygen, Carbon dioxide,
© 2018 SlidePlayer.com Inc. All rights reserved.