PHL 518 2ndMidterm (3 pages)
2nd semester 1427-28/2006-07
Dr. Amal Fatani
Dr. Nayira Abdel Baky
King Saud University
College of Pharmacy
Dept. of Pharmacology
Student Name
Student No.
I-Choose the correct answer(s):
1-Scorpions have been divided into two broad ecological categories:
" equilibrium" and "oportunistic"depending on
a-Their type of environment
b-Their life history strategies
c- Both a & b
2-As a consequence of the blocking effects of scorpion toxins on K+
channels, the action potential across excitable cell membranes becomes :
a- Prolonged
b-Shortened
c-Not affected
3-The neurological manifestations which present after scorpion
envenomation has been due to:
a-Hypertensive encephalopathy
b-Brain ischemia
c-Direct action of scorpion venom on the central nervous system.
4-Scorpion α-toxin
a-Slow or inhibit the Na+ current activation
b-Slow or inhibit the K+ current inactivation
c- Slow or inhibit the Na+ current inactivation
5-Scorpion toxins have been shown to modulate the activity of:
a-Voltage-dependent potassium channels
b-Ryanodine receptor/Ca2+-release channels
c- Ca2+-activated K+channels
6- The following are drugs acting on sodium channels EXCEPT:
a-Propafenone hydrochloride
b-Mepivacaine
c-Cilnidipine
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II-Complete the following:
1-The Na+ channel and K+ channel toxins mediate …………. actions
that can cause intense and persistent ……………. of autonomic nerves
with consequent ……………..of autonomic neurotransmitters.
2-Scorpions belong to the family Buthidae, from which the
genus……………, ………………..., ………………, Buthotus and
Heterometrus are located in the Old World, mainly North Africa, Middle
East and India .
3-Of the many types of transmembrane K+ channels, which mostly
affected by scorpion venom, are those activated by a rise in ……………
4-Charybdotoxin, which is a minor component of Leiurus quinquestriatus
scorpion venom, block the large conductance………………………… in
skeletal muscle T-tubules and cultured mammalian kidney cell
5-Scorpion venom toxins cause both …………….and………………..
Pulmonary edema . The first type has been attributed to acute left
ventricular failure and increased pulmonary vascular permeability
induced by vasoactive substances released upon the venom sting
6-…………………is a long-acting calcium channel blocker act mainly
on L-type Ca2+ channel, while …………………….is L/N-type Ca2+
channel blocker
7-Separation of venom components was performed either by high
performance liquid chromatography (HPLC) or …………………………
III-Indicate if the following statements are TRUE or FALSE and
correct the false:
( )1-Leiurus quinquestriatus and Androctonus crassicauda of the
family Buthidae are known as the “yellow scorpion” .
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)2-In Saudi Arabia, scorpions species or subspecies mainly
belonging to two families, the Buthidae and the Scorpionidae.
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)3-Venom from scorpions all over the world that belong to
Androctonus, Buthus, Centruroides, Leiurus quinquestriatus, and Tityus
species of the Scorpionidae family is highly toxic.
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)4-Venom neurotoxic proteins or peptides interacting non
specifically with various ionic channels in excitable membranes.
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)5-Toxins containing 60–70 amino acid residues are mainly active
on K+ channels. While short chain toxins composed of 30–40 amino acid
residues are mostly active on Na+ or Cl- channels.
----------------------------------------------------------------------------------------( )6-All scorpions venom are complex mixture of a wide array of
substances including mucopolysaccharides, hyaluronidase, phopholipase,
serotonin , histamine, protease inhibitors, histamine releasers and
polypeptidyl compounds.
----------------------------------------------------------------------------------------( )7-Scorpion envenomation can produce neurological manifestations
ranging from simple hypothermia to severe neurological manifestations
as coma and/or convulsions.
----------------------------------------------------------------------------------------( )8-The ryanodine receptor, plays a key role in excitation contraction
coupling of muscle tissues.
----------------------------------------------------------------------------------------( )9- The role of antivenom in the treatment of scorpion stings remains
controversial and the effectiveness of antivenom treatment depends on
the potency of the antivenom.
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Good Luck
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