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Biochemistry

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Signal Transduction: Theobromine Toxicity to Dogs

BIOCHM-SWYFPR

Theobromine, shown below, is an alkaloid found in chocolate that is structurally similar to caffeine and theophylline. When dogs eat chocolate, the heart, central nervous system, and kidneys are affected. Dogs can experience nausea, restlessness, muscle tremors, incontinence and diarrhea and ultimately death due to the toxicity of theobromine.

What is the mechanism by which theobromine toxicity occurs in dogs? Hint: Consider that the effects of caffeine and theophylline are mediated through a cAMP-dependent pathway.

NEUROtiker. "Theobromine." Wikipedia. Wikimedia Foundation, 20 Feb. 2007. Web. 29 May 2016.

Note: Theobromine is named for the genus of the cacao plant from which is was derived, Theobroma, which accounts for why the structure does not contain any bromine atoms; the above structure is correct.

A

Inhibits the breakdown of cAMP to AMP by a phosphodiesterase.

B

Inhibits the conversion of ATP to cAMP by adenylyl cyclase.

C

Promotes the breakdown of cAMP to AMP by a phosphodiesterase.

D

Promotes the conversion of ATP to cAMP by adenylyl cyclase.