Ch 7 - C hapter 7: Molecular Signaling in Neurons Binding...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 7: Molecular Signaling in Neurons Binding of NTs, hormones, growth factors activates the receptors to which it binds and in doing so stimulates cascades of intracellular reactions involving GTP binding proteins, 2 nd messenger molecules, protein kinases, ion channels, and many other effector proteins whose modulation temp. changes the physiological state of the target cell. Strategies of molecular signaling Paracrine signaling: chemical communication which acts over a longer range than synaptic trahnsmission and involves the secretion of chemical signals onto a group of nearby target cells Endocrine signaling: refers to the secretion of hormones into the bloodstream where they can affect targets throughout the body 3 requirements A molecular signal that transmits information from one cell to another A receptor molecule that transduces info provided by the signal A target molecule that mediates the cellular response EXAMPLE: norepinephrine binds to its receptor activating GTP proteins, which produces 2 nd messengers within the postsynaptic target, activates enzyme cascades, and eventually changes the chemical properties of numerous target molecules within the affected cell Signal Amplificaiton: occurs because individual signaling reactions can generate a much larger number of molecular products than the number of molecules that initiate the reaction Ex: a single norepinephrine molecule binding can generate many 1000 of 2 nd messenger molecules Such amplification can gurantees that a physiological response is evoked in the face of the otherpotentially countervailing influences Permits precise control of cell behavior over a wider range of times The activation of Signaling Pathways Cell impermeant: molecules typically bind to receptors assoc. with cell membranes such as NTs cannot readily traverse the PM of the target cell and must bind to a the extracellular portions of transmembrane receptor proteins typically short lived b/c they are readily metabolized
Background image of page 1

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

View Full DocumentRight Arrow Icon
Cell permeant: molecules that can cross the PM to act directly on receptors that are inside the cell Examples include steroid and thyroid hormones and retinoids Are able to cross the PM and bind to receptors in the cytoplasm or nucleus of target cells Cell associated molecules: molecules that act only on other cells that are physically in contact with the cell that carries such signals Examples include proteins and neural cell adhesion molecules that influ. Growth Receptor types Binding of signal molecules causes a conformational change in the receptor which then triggers the subsequent signaling cascade within the affected cell Channel-linked: also called ligand gated ion channels; have the receptor and transducing functions as part of the same protein molecules; interaction with the chemical signaling with the binding site of the receptor causes the opening/closing of an ion channel pore in another part of the same molecule
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 8

Ch 7 - C hapter 7: Molecular Signaling in Neurons Binding...

This preview shows document pages 1 - 3. Sign up to view the full document.

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