Effect of blocking agents

Effects of Blocking Agents on Antibody Penetration. Combined Incubation Step. 

I 10. The answer is a. (Hardman, p 1302J Cyclophosphamide is classified as a poly functional alkylating drug that transfers its alkyl groups to cellular components. The cytotoxic effect of this agent is directly associated with the alkylation of components of DNA. Methotrexate and 5-FU are classified as anti metabolites that block intermediary metabolism to inhibit cell proliferation. Tamoxifen is an antiestrogen compound. Doxorubicin is classified as an antibiotic chemotherapeutic agent. 

Antipsychotic agents are also used for a diversity of other indications like hiccups, Tourette s syndrome, aggressive behavior in children and the elderly and alcohol withdrawal syndrome. Some of them are also used in anesthesia as they can potentiate the sedative, analgesics or anesthetic effects of other agents. Antipsychotics which are mainly active by blocking dopamine activity have also an effect on chemoreceptor trigger zone and may therefore be used as anti-emetics. 

It soon became evident that no available antidotes could block the pharmacologic activity of these chemicals, alleviate the signs and symptoms of toxicity, or restore normal bodily functions after exposure. Atropine readily antagonized the muscarinic actions, including those in the central nervous system (CNS), but elicited no reversal of the nicotinic effects. Better forms of therapy were sought, particularly to alleviate the nicotinic effects of anticholinesterase agents. 

Nefazodone has some unusual pharmacological properties, not only inhibiting serotonin uptake, but also blocking the 5-HT 2a receptor. It may be that the antidepressant effect of serotonin agents is due to mediation of 5-HT transmission in the absence (or even the blockade) of 5-HT2a transmission. As a result of these actions, nefazodone is even more specific in terms of affecting a subtype of serotonin receptor than are the SSRIs or venlafaxine. 

At least two groups have tested the effects of blockade of the anion channel on the production of O by PMNs Gennaro and Romeo found that the production of O by bovine PMNs was reduced by the blockers of the anion channels SITS (4-acetamido-4 -isothiocyanostilbene-2,2 -disulfonic acid) and ANS (anilino naphthalene disulfonic acid). The consumption of Oj was unaffected. In accord with the expectation if the effects of these agents were to block the anion channel, replace-... 

Both calmodulin and a calcium- and calmodulin-dependent phosphodiesterase activity occur in dispersed bovine parathyroid cells (20.). Some of the phenothiazines blocking the dopamine receptor in this tissue inhibit the interaction between calmodulin and the calmodulin-dependent phosphodiesterase. A series of experiments have tested the possibility that calmodulin might play a role in the effects of these agents on the parathyroid gland. The dopamine antagonists examined were weak inhibitors of calmodulin-stimulated phosphodiesterase activity (Table II). 

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