Modes of communication
- direct cell-cell signalling(really short distance)
- neurotransmitters-
- signaling by secreted molecules(long - distance)
What is endocrine signalling
- signalling by secreted molecules
- where endocrine cells secrete hormones that are carried through the circulation to act on target cells
What are the derivatives of cholesterol
- steroid hormones are derivatives of cholesterol
- the hydrophobic nature allows diffusion across membranes
WHat happens in the presence of hormones in cell signalling
changes conformation of receptor, displacing HDAC (corepressor) for HAT (coactivator) that is bound to the thyroid hormone receptor
What are thyroid hormones
non steroid chemical hormones that bind DNA in an inactive form that becomes active when bound with hormone
Paracrine signalling
short distance communication mode in which molecule released by one cells acts on target cells
what is Paracrine signalling
short distance communication mode (neurotransmitters) in which molecule released by one cells acts on target cells
Neurotransmitters as paracrine ligands
- hydrophilic
- release stimulated by action potential in neuron
- bind cell surface receptors
- depolarization
- also bind G protein couples receptors
Nitric acid as paracrine ligands
- difuses out of cell freely
- extremely unstable
- induction of NO synthesis in endothelial cells of blood vessels by release of acetylcholine from neurons
- diffusion of NO to surrounding smooth muscles
what can limit a ligand’s effect on target cells
- chemical nature of ligand
- distance from target cell
- receptors on target cell
- intercellular molecules
