Cell signals and control pathways

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Cell signals and control pathways

• List and describe the components in specific 2nd
  messenger signal transduction pathways
• Define each of the following and predict their
  effect on signal transduction
• agonist and antagonist for one receptor
• receptor isoforms (one ligand, gt1 receptor)
• one ligand on one receptor (tonic control)
• two antagonistic ligands on one tissue

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http//www.blackwellpublishing.com/matthews/neurot
rans.html
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Class problem set

• 1. Norepinephrine (NE) is a large protein. Where
  will receptors for NE be?
• inside the target cell or on the target cell
  membrane
• 2. When NE binds an ?1 receptor on a cells
  membrane, there is an increase in IP3 and DAG in
  the cell. What membrane bound amplifier enzyme is
  activated to cause the IP3 and DAG increase?
• 3. What ion will be increased in the ICF due to
  IP3 ?
• 4. What ICF enzyme will be activated by DAG?

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Example of two ligands and two receptor isoforms
Norepinephrine or Epinephrine
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Tonic control through one signal molecule
?
?
?
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• Predict the effect of the following on blood
  vessel smooth muscle controlled by catecholamines
  on adrenergic receptors muscle cell receptor
  type
• ?1 ?2
• increased NE release
• decreased NE release
• addition of ?1 agonist
• addition of ?2 agonist
• addition of ?1 antagonist
• addition of ?2 antagonist
• addition of ?1 antagonist

1. Constrict Dilate
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Control pathways

• - List the components of a control pathway and
  identify those components in specific neural and
  endocrine reflex pathways.

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Ex/ control of lactation
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Negative feedback - maintains homeostasis
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Positive feedback - increases response
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Example control pathways

• You stand up. (A decision in the brain is
  transmitted by a motor neuron that releases
  neurotransmitter to cause coordinated leg muscle
  contraction.)
• Decreasing plasma Ca2 is detected by the
  parathyroid gland cells. The glands release PTH
  in response. PTH will remove some Ca2 from bone
  and increase plasma Ca2.
• You breath in carbon monoxide. You have no
  receptors for this gas.