Test 173 (modified from MRCOphth/MRCS Questions, 2003)
1. Intracellular messengers include: 
a. cyclic guanosine monophosphate (cGMP)
b. inositol triphosphate (IP3)

c. cyclic adenosine monophosphate (cAMP)

d. diacylglycerol


2. The following are true about inositol triphophate (IP3):

a. it is increased by activation of a1-adrenoreceptors

b. it is produced by the action of phospholipase C,
    a membrane bound enzyme

c. it acts as second messengers

d. it binds to the membrane of the endoplasmic reticulum 
    and opens the calcium channels

e. it causes smooth muscle contraction

3. The following are true about antifungal medications:
a. polyene macrolids bind to the ergosterol in the 
    fungal cell membrane and produce pores

b. imidazoles prevents ergosterol synthesis by inhibiting 
    the enzyme squalene oxidase

c. allylamines inhibit fungal lipid synthesis in the cell 

d. flucytosine inhibits fungal DNA synthesis

e. griseofulvin interferes with microtubule formation

. 4. With regard to the eye:
a. parasympathetic stimulation causes pupil constriction

b. pin-point pupil results from opiate overdose

c. inhibition of the parasympathetic pathway to the 
    ciliary muscle causes the lens to becomes thinner and 
    more elongated

d. the ciliary muscle contains muscarinic M1 receptors

e. pilocarpine causes miosis by relaxing the dilator muscle
   of the pupil

5. Stimulation of a2-adrenoreceptors causes:

a. contraction of blood vessels

b. decreased intraocular pressure

c. relaxation of the iris dilator

d. eyelid retraction

e. platelet aggregation

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