Cell signaling  a. Epinephrine can cause either vasodilation or vasoconstriction, depending on the specific type of adrenergic receptor that it activates. b. Alpha-bungarotoxin is a snake toxin that specifically targets the nicotinic acetylcholine receptor. c. Upon activation by insulin, the insulin receptor directly phosphorylates substrate proteins. d. Both a) and b) are correct and c) is incorrect e. Statements a), b) and c) are all correct

Explain the role, using diagrams wherever possible, of G protein coupled receptors mediating the following physiological effects. a. Positive inotropic and positive chronotropic effects in the heart b. Vasoconstriction in vascular smooth muscle cells.

Activated G proteins can ... a) ... cause ion channels to open or close. b) ... increase the synthesis of cAMP. c) ... activate adenylate cyclase. d) ... increase the activity of IP3.

Endothelins are 21-amino acid vasoconstricting peptides produced primarily in the endothelium. They have an important role in vascular homeostasis. Endothelin activates G protein-coupled receptors  (GPCRs) ETA or ETB on a target cell.  Which subunit of heterotrimeric G protein is released when the receptor is activated? a.) gamme b.) beta c.) alpha

Which of the following statements is true?   Question 2 options:   a)  All cells will respond to the hormonal signal because hormones are broadcast throughout the body.   b)  The regulation of inflammatory responses at the site of an infection is an example of paracrine signaling.   c)  Paracrine signaling involves the secretion of stimuli into the bloodstream for distribution throughout the organism.   d)  The axons of neurons typically signal target cells using membrane-bound signaling molecules that act on receptors in the target cells.

Please identify the incorrect statement about hormone signaling: A) Cystolic receptors bind to hydophobic hormones and transport them into the nucleus where they directly influence protein synthesis.  B) Hydropholic hormones cannot pass through the plasma membrane without help. Therefore, there are transport proteins that carry the hydrophillic hormones to the cytosol where it can bind its receptor  C) Hydrophilic hormone signalling involves membrane receptors that have the ability to activate adenylyl cyclase, producing cAMP. cAMP then affects the activity of numerous proteins in the cytoplam.  D) Hydrophobic hormones easily enter the plasma membrane. Therefore, there is no need for hydrophinic hormone receptors to be on the extracellular surface.

Steroid hormones ... a) ... transmits its effects mainly by binding to membrane receptors. b) ... are water soluble. c) ... conveys its effects mainly through so-called second messengers. d) ... is transported in the blood by means of carrier protein.

A.Where are Epinephrine and Norepinephrine made? (cells, organ) B.What organ/or cells secrete them? (may differ from site of formation) C.What stimulates their secretion? Explain negative feedback control of secretion. D.Where do they work (target) E.What do they regulate: physiological outcome?

Design a novel drug for treatment for overactive bladder syndrome which does not target the muscarinic M3 receptors directly, but rather targets one of the second messenger signalling molecules within the smooth muscle cells as a result of muscarinic M3 receptor activation. Which second messenger molecule would you choose to target? Justify your choice and explain how targeting this second messenger pathway would result in the reduction of bladder smooth muscle contraction.

A GRK inhibitor would have what effect on GPCR inactivation in the presence of a GPCR agonist? (a) it would decrease it; (b) it would maintain the same rate of inactivation; (c) it would increase it.