Stimulant Action

Morphine. This alkaloid exerts both a depressing and a stimulating action on the central nervous system, the depression affecting the brain especially the sensation of pain and the respiration the cerebral motoi functions are less affected. The stimulant action in the cord is best seen in the cold-blooded animals, when it may develop into tonic convulsions. In higher animals, but rarely in man, there may be some indication of this stimulant action. In cats it may also involve the motor areas, and they... 

Codeine (morphine methyl ether) resembles morphine in its general effect, but is less toxic and its depressant action less marked and less prolonged, whilst its stimulating action involves not only the spinal cord, but also the lower parts of the brain. In small doses in man it induces sleep, which is not so deep as that caused by morphine, and in large doses it causes restlessness and increased reflex excitability rather than sleep. The respiration is slowed less than by morphine (cf. table, p. 261). Cases of addiction for codeine can occur but according to Wolff they are rare. The best known ethers of morphine are ethylmorphine and benzyl-morphine [cf., table, p. 261), both used to replace morphine or codeine for special purposes. 

Omission of the side chain hydroxyl group from molecules based on epinephrine or ephedrine does not abolish the sympathomimetic activity of the resulting compounds. Many of these agents exert a considerable stimulant action on the central nervous system. As such, drugs in this class have been widely used—and... 

Catecholamines are also intimately involved in cardiac function, with 3-sympathetic agonists having a generally stimulant action on the heart. Some effort has thus been devoted to the synthesis of agents that would act selectively on the heart. (Very roughly speaking, 3 -adrenergic... 

Colas stimulate digestive juices, and carbonated water speeds the digestion, and this combination of effects, along with the stimulant action of the two alkaloids, can make a big difference to someone who is not feeling well. 

Gawin FH, Ellinwood EH Jr Cocaine and other stimulants actions, abuse, and treatment. N Engl J Med 318 1173-1182, 1988... 

It has been shown that glycolic acid has a kerat-olytic, germinative layer and a fibroblast stimulating action. 

In contrast to the nicotinic antagonists and indeed both nicotinic and muscarinic agonists, there are a number of muscarinic antagonists, like atropine, hyoscine (scopolamine) and benztropine, that readily cross the blood-brain barrier to produce central effects. Somewhat surprisingly, atropine is a central stimulant while hyoscine is sedative, as least in reasonable doses. This would be the expected effect of a drug that is blocking the excitatory effects of ACh on neurons but since the stimulant action of atropine can be reversed by an anticholinesterase it is still presumed to involve ACh in some way. Generally these compounds are effective in the control of motion but not other forms of sickness (especially hyoscine), tend to impair memory (Chapter 18) and reduce some of the symptoms of Parkinsonism (Chapter 15). 

Loeomotor aetivity has historically been used as an index of psychostimulant effects. Simple assessment of amount of loeomotor activity can provide the basis for anatomical as well as pharmaeologieal analysis of the neural substrates that mediate the behavioral expression of stimulant action. More sophisticated behavioral measurement systems ean reeord multiple measures of activity and describe spatial and temporal patterning of loeomo-tion. In such systems, qualitative aspects of behavioral activation can be evaluated by examining the entire activity profile. A comparison of the effects of novel drugs with those produced by well-characterized substanees may lead to a better understanding of their mechanisms of action and subjective properties. 

The psychotropic (stimulant) action of amphetaminil (57) may be intrinsic or due to in vivo hydrolysis of the a-aminonitrile function—akin to a cyanohydrin—to liberate amphetamine itself. It is synthesized by forming the Schiff s base of amphetamine with benzaldehyde to give 56, and then nucleophilic attack on the latter with cyanide anion to... 

Rockhold, R.W. Glutamatergic involvement in psychomotor stimulant action. Prog. Drug Res. 50 155, 1998. 

Methylenedioxymethamphetamine (MDMA, or Ecstasy ) is an illicit drug used by young adults who attend rave dance parties in the U.S., Europe, and elsewhere. The allure of MDMA is related to its unique psychoactive effects, which include amphetamine-like stimulant actions, coupled with feelings of increased emotional sensitivity and closeness to others.1-2 Epidemiological data indicate that MDMA misuse among children and adolescents is widespread in the U.S.3-4 In... 

B. W. Greatex, S. J. Brodie, R. H. Fumeaux, S. M. Hook, W. T. McBumey, G. F. Painter, T. Rades, and P. M. Rendle, The synthesis and immune stimulating action of mannose-capped lysine-based dendrimers, Tetrahedron, 65 (2009) 2939-2950. 

The stimulating action of methylene blue and other reducible dyes on MHb reduction has long been established. However, this function is not constant, and may even be absent (H22, H23). In beef erythrocytes, and in MHbR prepared from yeast, no stimulating effect of methylene blue could be observed (A6, H22). When beef blood enzyme was boiled, a substance was obtained which activates the human MHbR without... 

Dichloro-isoprenaline was the first [3-adrenoceptor antagonist to he described (6). It was discovered in a search for specific (3-stimulants as bronchodilators. This compound is a partial agonist, i.e. it can antagonise the action of isoprenaline hut itself is a (3-stimulant. (The stimulant action of dichloro-isoprenaline is readily demonstrated in an animal depleted of natural catecholamines ( with say reserpine). In this type of preparation it will stimulate say heart rate to a maximum of 70% of that produced hy isoprenaline itself). 

Similarly, where a stimulation action (e.g., antipyretic effect of NSAIDS through thermolysis or production of cAMP by bronchodilator beta-2 agonisU ) is involved, the stimulation response... 

Evans MA, Harbison RD, Brown DJ, Forney RB. (1976). Stimulant actions ofdelta9-tetrahydrocannabinol in mice. Psychopharmacoiogy (Beriin). 50(3) 245-50. 

In the U. K., it has been found quite recently that substituted dihydropy-ridazinones (60) act as combined y9-adrenoceptor antagonists and vasodilators. The effect of stereochemistry on biological activity has been discussed [180], Other dihydropyridazinone derivatives which show )S-sympatholytic and cardiac stimulant actions are described in a patent [181],... 

The work described in this paper was partially financed by E.E.C. Grant ST2J-0030 (Stimulation Action), which is gratefully acknowledged. 

These compounds competitively inhibit phosphodiesterase, resulting in an increase in cyclic AMP (see Box 14.3) and subsequent release of adrenaline. This leads to the major effects a stimulation of the central nervous system (CNS), a relaxation of bronchial smooth muscle, and induction of diuresis. These effects vary in the three compounds. Caffeine is the best CNS stimulant, and has weak diuretic action. Theobromine has little stimulant action, but has more diuretic activity and also muscle relaxant properties. Theophylline also has low stimulant action and is an effective diuretic, but it relaxes smooth muscle better than caffeine or theobromine. 

Inverse enantioselectivity at another receptor. An enantiomer may possess an unfavorable configuration at one receptor that may, however, be optimal for interaction with another receptor. In the case of dobutamine, the (+)-enantiomer has affinity at p-adreno-ceptors 10 times higher than that of the (-)-enantiomer, both having agonist activity. However, the a-adrenoceptor stimulant action is due to the (-)-form (see above). 

Histamine also evokes a copious secretion of highly acidic gastric juice from the gastric glands at doses below those that influence blood pressure (32). This effect of histamine is mediated through 2 receptors on the parietal cells. The importance of this effect in scombroid poisoning is not knowi. Histamine also has some stimulant actions on salivary, pancreatic, intestinal, bronchial, and lacrimal secretions (32), but these effects are relatively unimportant. 

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