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Biomedical subjects

P Kalix

Publications and source records attributed to P Kalix.

At least 37 records · Page 2Linked to original sources
PubMed1984

Effect of the alkaloid (-)-cathinone on the release of radioactivity from rat striatal tissue prelabelled with 3H-serotonin.

The alkaloid (-)-cathinone, which accounts for the stimulating properties of khat leaves, has a pharmacological profile closely resembling that of (+)-amphetamine. Since amphetamine is known to induce release at CNS serotonin storage sites, experiments were performed to determine whether (-)-cathinone also displays this aspect of amphetamine action. When the effects of (-)-cathinone and (+)-amphetamine on the release of radioactivity from rat striatal tissue prelabelled with 3H-serotonin were compared, it was found that (-)-cathinone had a releasing effect similar to that of (+)-amphetamine, although it was only one third as potent. Thus, the khat alkaloid (-)-cathinone appears to share an important effect of (+)-amphetamine on serotoninergic neurotransmission.

Alkaloids↗
PubMed1984

Khat: an amphetamine-like plant material.

The chewing of leaves of the khat shrub is common in certain countries of East Africa and the Arabian peninsula, and many khat users are subject to psychic dependence on the drug. The syndrome observed after khat consumption is characterized by a certain degree of CNS stimulation and by sympathomimetic effects; it is reminiscent of that induced by amphetamine.Recently, the alkaloid (-)-cathinone has been isolated from khat leaves and this substance produces effects in animals that are analogous to those of (+)-amphetamine and that correlate well with the effects observed in humans after khat consumption. Furthermore, it has been shown that (-)-cathinone acts by the same mechanism as (+)-amphetamine, i.e., by inducing release at physiological catecholamine storage sites. Taken together, these studies indicate that khat must be considered an amphetamine-like material.

Alkaloids↗
PubMed1984

Recent advances in khat research.

Khat leaves are widely used as a stimulant in East Africa and the Arabian Peninsula and the effect of the material was formerly believed to be due to its content of norpseudoephedrine. Recently, however, a new alkaloid, cathinone, has been discovered in khat, and this substance was found to be a potent compound with a pharmacological profile closely resembling that of amphetamine. It was also found that cathinone has the same mechanism of action as amphetamine, i.e. that it causes release at physiological catecholamine storage sites. The present report summarizes the pharmacology of cathinone and shows that this alkaloid must be considered to be the main active constituent of khat.

Alkaloids↗
PubMed1983

A comparison of the catecholamine releasing effect of the khat alkaloids (-)-cathinone and (+)-norpseudoephedrine.

Consumption of khat leaves produces symptoms that are similar to those caused by amphetamine. The experiments reported in the following describe the effect of the two khat alkaloids (-)-cathinone and (+)-norpseudoephedrine at the cellular level. Both were shown to induce release from physiological catecholamine storage sites. Peripheral noradrenaline sites (rabbit heart) were observed to be more sensitive than CNS dopamine sites (rat nucleus accumbens). In the latter organ, which is believed to be involved in amphetamine hypermotility, (-)-cathinone was considerably more potent than (+)-norpseudoephedrine.

Alkaloids↗
PubMed1982

The amphetamine-like releasing effect of the alkaloid (-)cathinone on rat nucleus accumbens and rabbit caudate nucleus.

1. (-)Cathinone, a new alkaloid from khat leaves, has recently been reported to have amphetamine-like behavioral effects. In order to investigate the effects of this compound on the cellular level, slices of rat nucleus accumbens, prelabelled with 3H-dopamine, were superfused with solutions of (-)cathinone. 2. It was found that (-)cathinone, as (+)amphetamine, enhanced the release of radioactivity from rat nucleus accumbens tissue. 3. In similar experiments on rabbit caudate nucleus it was observed that the catecholamine reuptake inhibitors benztropine, nomifensine and mazindol were able to block the (-)cathinone-induced release, indicating that the alkaloid has to penetrate to intraneuronal sites in order to evoke release. 4. It is concluded that the pharmacological similarity between (-)cathinone and (+)amphetamine extends to the cellular level and that the behavioral effects of (-)cathinone are due to stimulation of release from central catecholamine storage sites.

Alkaloids↗
PubMed1982

The effect of the alkaloid (-)cathinone on the motor activity in mice.

Khat leaves, widely used as a stimulant in East Africa and the Arab Peninsula, contain the alkaloid, (-)cathinone. This substance was found to cause in mice an increase of locomotor activity characterized by a dose-effect relationship typical for amphetamine. Furthermore, the effect of (-)cathinone was inhibited by pretreatment of the animals with the neuroleptics haloperidol, spiroperidol, pimozide, flupentixol and butaclamol. Pretreatment with reserpine reduced the effect of (-)cathinone moderately; in reserpinized mice the effect of (-)cathinone was antagonized by the uptake inhibitors mazindol and nomifensine. Together, these observations indicate that the pharmacology of (-)cathinone hypermotility closely parallels that of amphetamine hypermotility. The results suggest that the stimulating properties of khat leaves are due to the presence of an alkaloid with amphetamine-like effects.

Alkaloids↗
PubMed1981

Cathinone, an alkaloid from khat leaves with an amphetamine-like releasing effect.

Khat leaves, widely used as a stimulant in East Africa and the Arab Peninsula, contain the alkaloid (--)-cathinone. The effects of this substance on the efflux of radioactivity from rabbit striatal slices prelabelled with 3H-dopamine were examined. It was found that low concentrations of (--)cathinone enhance the release of radioactivity in a dose-dependent manner, and that (--)cathinone was capable of sustaining the enhanced release induced by (+)amphetamine. Pretreatment of the tissue with cocaine, which is known to prevent the induction of release by (+)amphetamine, inhibited the efflux increase caused by (--)-cathinone. These observations suggest that amphetamine and the active principle of khat leaves have an analogous mechanism of action.

Alkaloids↗
PubMed1980

A constituent of khat leaves with amphetamine-like releasing properties.

Khat leaves, which are widely abused as a stimulant, contain the alkaloid (--)-cathinone. The effect of this compound on the efflux of radioactivity from rabbit striatal tissue prelabelled with [3H]dopamine was examined. (--)-Cathinone enhanced the release of label, and was found to have a potency similar to that of (+)-amphetamine. The observation demonstrates that the khat alkaloid also has amphetamine-like effects at the cellular level.

Alkaloids↗
PubMed1980

Hypermotility of the amphetamine type induced by a constituent of khat leaves.

Khat leaves, widely used as a stimulant in East Africa and the Arab Peninsula, contain the alkaloid, (-)-cathinone. The effects of this substance on the locomotor activity of rats were compared to those of (+)-amphetamine. Both substances were found to induce a similar degree of hypermotility. Furthermore, the effect of (-)-cathinone on the locomotor behaviour of hypophysectomized rats was analogous to that reported for (+)-amphetamine in such animals. The results support the claim that the symptoms caused by the chewing of khat are amphetamine-like.

Alkaloids↗
PubMed1979

Prostaglandin E1 raises the cAMP content of peripheral nerve tissue.

Prostaglandins of the E type have been found to increase the cAMP content in peripheral nerve tissue of several species. In rabbit vagus nerve, for example, the effect is rapid (1--5 min), it can be elicited by 10(-6) M PGE1 and it is maximal at 10(-5) M. In this preparation the increase of the cAMP content caused by PGE1 is about 4-fold, whereas it is about 2-fold in the vagus of calf. PGE1 also causes an increase in cAMP level in the superior cervical ganglion of calf, rat and rabbit. In these tissues, however, the presence of a phosphodiesterase inhibitor is required for cAMP accumulation.

Animals↗
PubMed1976

Effect of decentralization and glucose withdrawal on the potassium-induced cAMP increase in the rabbit superior cervical ganglion.

The concentration of cAMP in the isolated rabbit superior cervical ganglion (SCG) increases when the tissue is exposed to high potassium media for short periods. The increase was found not to be affected by agents that are known to potentiate or to antagonize the postsynaptic effects of acetylcholine. Pretreatment of the rabbits with various sympaticolytic substances did not appear to affect the cAMP increase in the isolated SCG. It was found that the K+-induced cAMP synthesis occurred neither in ganglia which had been decentralized 3 days before isolation nor in intact ganglia preincubated in a glucose-free medium. Under both these conditions the effect of potassium declines with a time course which is characteristic for the degeneration of the presynaptic terminals. These terminals therefore, appear to be the most likely site for the cAMP increase.

Animals↗
PubMed1976

Evidence of depolarization-induced cAMP increase in the superior cervical ganglion of several mammalian species.

1. The activation of cAMP synthesis resulting from exposure of superior cervical ganglion (SCG) tissue to high K+ solutions observed in calf has been found to occur in three other mammalian species, namely rat, cat, and rabbit. 2. The cAMP accumulation in the ganglion of calf is much less pronounced than that occurring in the other species. The enhancing effect oftheophylline on the increase of cAMP was found to be much greater in the SCG of calf than in that of other species. When veratridine was used as the depolarizing agent the species differences were found to be similar to those observed after potassium stimulation. 3. The effectiveness of several other depolarizing agents in causing an increase in the cAMP level was tested in rabbit SCG.

Animals↗