Wrong. There is a curve which represents the curve for acetylcholine in a preparation pretreated with succinylcholine. Go back to Item VIII and think about it again.

Wrong. Cocaine modifies norepinephrine effects. Before you go back to Item VI, review the pharmacological effects and mechanism of action of cocaine.

Wrong. Tyramine would increase blood pressure mainly through release of norepinephrine from the nerve endings. However, there would be a decrease of the heart rate mediated through stimulation of carotid baroreceptors. Go back to Item XV.

Wrong. You do not understand the concept of potency and intrinsic activity. Review these terms in the Glossary of Terms and Symbols Used in Pharmacology (Course Manual, Chapter 3), and then go back to Item I.

Right. Acetylcholine would decrease blood pressure and induce secondary reflex tachycardia. There is, however, another treatment which would produce similar effects. Go back to Item XIX and try to find it.

Wrong. Review the cardiovascular effects of catecholamines and histamine before going back to Item XIV.

Right. Hexamethonium would prevent both the effects of distal vagal nerve stimulation and carotid occlusion by blocking transmission at the parasympathetic and sympathetic ganglia. Go to Item XIV.

Wrong. Chlorpheniramine modifies the effect of histamine on blood vessels. Before you go back to Item V, review the pharmacology of chlorpheniramine and other antihistamines.

Wrong. There is a curve which represents the curve for norepinephrine in the presence of phentolamine. Go back to Item VII and think about it again.

Wrong. Histamine would produce slight tachycardia, but it would markedly decrease the blood pressure by dilation of small blood vessels. Go back to Item XIV.

Very good. I hope you chose a and c as the right answers. Go to Item XVIII.

Right. A low dose of epinephrine decreases blood pressure and this decrease would be enhanced by blockade of alpha adrenergic receptors. Go to Item XIX.

Right. Ipratropium is a pharmacological antagonist of acetylcholine because it acts at the same site (receptor) as acetylcholine. Go to Item III.

Right. Methoxamine selectively stimulates the alpha adrenergic receptors and, therefore, would produce an increase of blood pressure and reflex bradycardia. There is, however, another drug or drug combination which would induce similar changes. Go back to Item XVI and try to find it.

Wrong. A reversible competitive antagonist acts by competing with the agonist for receptor binding. Therefore it is possible to overcome a competitive blockade by increasing the concentration of agonist. The presence of a competitive antagonist usually shifts the dose-effect curve to the right, but it does not change the maximal effect. Go back to Item III.

Wrong. Pretreatment with d-tubocurarine blocks the effects of acetylcholine. Therefore, acetylcholine cannot have greater effect in a preparation pretreated with d-tubocurarine than when it is given alone. Go back to Item X.

Wrong. There is a curve for norepinephrine in the presence of cocaine. Go back to Item VI and think about it again.

Wrong. There is only one true statement listed. Go back to Item XVIII and try to find it.

Wrong. There is only one drug which would diminish the blood pressure changes resulting from both distal vagal nerve stimulation and carotid occlusion. Go back to Item XIII and try to find it.

Right. The intrinsic activity depends on the amount of biological effect produced per unit of drug-receptor complex formed. An agent producing greater maximum effect (in our case drug B) has the greater intrinsic activity. There is, however, one other true statement in this item. Go back to Item I and try to find it.

Right. Phenoxybenzamine binds irreversibly to alpha adrenergic receptors. and therefore produces a non-competitive block of these receptors. The effect of phenylephrine, which stimulates vascular alpha receptors, is inhibited in a preparation pretreated with phenoxybenzamine. Go on to Item X.

Very good. I hope you consider histamine and acetylcholine to be the right answer. You are now at the end of the program and I hope that you learned something in answering it.

Wrong. Pretreatment with succinylcholine blocks the effect of acetylcholine at the neuromuscular junction. Therefore, acetylcholine cannot have greater effect in a preparation pretreated with succinylcholine than when it is given alone. Go back to Item VIII.

Very good. Propranolol would decrease, and atropine and hexamethonium would increase, the heart rate changes observed following the administration of a high dose of epinephrine. Go to Item XVII.

Wrong. There is only one drug or procedure which would simultaneously increase both blood pressure and heart rate. Go back to Item XII and try to find it.

Right. Stimulation of the distal vagus would decrease both the heart rate, due to direct parasympathetic inhibition of the sinus node, and the blood pressure, due to decreased cardiac output. Go on to Item XII.

Right. Physostigmine potentiates the effects of acetylcholine by inhibiting acetylcholinesterase, an enzyme which hydrolyzes acetylcholine. Potentiation of an agonist effect shifts the dose-effect curve to the left. Go to Item V.

Wrong. Chemical antagonism is caused by a combination of agonist with antagonist, resulting in inactivation of the agonist. Phenoxybenzamine antagonizes norepinephrine by decreasing the number of alpha-receptors available for norepinephrine. Go back to Item II.

Wrong. Phentolamine would abolish the effect of carotid occlusion, but not the effect of distal vagal nerve stimulation. Go back to Item XIII.

Very good. All of the listed treatments would simultaneously increase the blood pressure and decrease the heart rate. Go on to Item XVII.

Wrong. There is one treatment listed which does not simultaneously decrease the blood pressure and increase the heart rate. Go back to Item XVII and try to find it.

Wrong. The effect of norepinephrine in a preparation pretreated with phentolamine is represented by a different curve. Go back to Item VII.

Wrong. Histamine administration would decrease the blood pressure not the heart rate. The heart rate after histamine is usually slightly elevated because decrease of the blood pressure induces sympathetic activation through baroreceptors. Go back to Item XI.