Tropacocaine

Differential inhibition of synaptosomal accumulation of [3H]-monoamines by cocaine, tropacocaine and amphetamine in four inbred strains of mice.[Pubmed:2626447]

Pharmacol Biochem Behav. 1989 Sep;34(1):165-72.

The relative ability of cocaine, Tropacocaine and amphetamine to inhibit the uptake of [3H]norepinephrine (NE), [3H]dopamine (DA) and [3H]5-hydroxytryptamine (5HT) was examined in whole brain synaptosomes from BALB, C3H, C57BL and DBA inbred mouse strains. With inhibition of [3H]NE uptake, synaptosomes from BALB and C57 mice were substantially more sensitive to cocaine inhibition than those from DBA or C3H. Moreover, with BALB and C57 tissue, amphetamine was as potent as cocaine, whereas with C3H and DBA, amphetamine and Tropacocaine were much less potent inhibitors of [3H]NE uptake. With respect to [3H]DA accumulation, synaptosomes from BALB, C57 and DBA were equally sensitive to cocaine inhibition, while C3H synaptosomes were significantly less sensitive. In each of the four strains, amphetamine was more potent than cocaine, and Tropacocaine far less potent. The relative potencies of the three drugs varied significantly among the four strains. With [3H]5HT accumulation, synaptosomes from DBA were exquisitely sensitive to cocaine inhibition, followed by BALB and lastly by C57 and C3H. In each of these strains, amphetamine and Tropacocaine were equipotent at [3H]5HT inhibition, and less potent than cocaine. The results suggest that there are pronounced genetic differences in sensitivity to monoamine uptake inhibition by cocaine, which may arise from genetic differences in either carrier topology or other site of cocaine interaction. The results further suggest that genetic behavioral differences to cocaine and amphetamine may involve complex neurotransmitter interactions.

Cardiovascular effects of tropacocaine in conscious and anesthetized rabbits: lack of evidence for neuro-cardiac interactions and acute neurotoxicity.[Pubmed:7603635]

Neurotoxicology. 1995 Spring;16(1):145-51.

The cardiovascular effects of Tropacocaine, a structural analog of cocaine, were investigated in both conscious and anesthetized New Zealand white rabbits to determine if such effects were mediated through the CNS as had been demonstrated with cocaine, i.e., did a neuro-cardiac pathway exist? To facilitate the requisite cardiovascular measurements in both urethane- and pentobarbital-anesthetized animals, the right femoral artery and vein were cannulated for the measurement of arterial blood pressure and subsequent delivery of drugs, respectively. In addition, urethane-anesthetized animals had a branch of the left renal nerve isolated and multiunit renal nerve activity was monitored to obtain measures of sympathetic nerve activity originating from the CNS. Animals utilized in conscious experiments were surgically prepared 3 days prior to drug administration by placing canulae in the femoral artery and vein that were tunneled subcutaneously to the back between the scapulae. ECG and respiratory activity were also monitored in each animal. Doses of 0.3, 1, 3, and 10 mg/kg of Tropacocaine were administered in both an ascending and descending fashion at 15 min intervals to 5 animals in each group, i.e., conscious, urethane-, and pentobarbital-anesthetized. In urethane-anesthetized animals a comparison was made between sympathetic renal nerve activity, systolic and diastolic blood pressure, respiratory rate, and heart rate. No pressor effects were observed and the changes in renal nerve activity could not be assigned as the cause of the observed depressor effects at the higher doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination and in-depth chromatographic analyses of alkaloids in South American and greenhouse-cultivated coca leaves.[Pubmed:8118557]

J Chromatogr A. 1994 Jan 21;659(1):163-75.

Methodology is described for the detection and/or determination of cocaine and minor alkaloids in South American coca as well as in greenhouse- and tropical-cultivated field coca of known taxonomy. Coca leaf from Bolivia, Peru, Ecuador and Colombia were subjected to the determination of cocaine, cis- and trans-cinnamoylcocaine, Tropacocaine, hygrine, cuscohygrine and the isomeric truxillines. The greenhouse samples were cocaine-bearing leaves of the genus Erythroxylum and included E. coca var. coca, E. novogranatense var. novogranatense and E. novogranatense var. truxillense, and the alkaloids determined were cocaine, ecgonine methyl ester, cuscohygrine, Tropacocaine and the cinnamoylcocaines. The tropical-cultivated coca were E. novogranatense var. novogranatense and E. coca var. coca. Cocaine and minor alkaloids were isolated from basified powdered leaf samples using a toluene extractant, followed by acid-Celite column chromatography. The isolated alkaloids were determined by capillary gas chromatography with flame ionization or electron-capture detection. Methodology is also presented for the isolation and mass spectral analysis of numerous trace-level coca alkaloids of unknown structure.

Effects of benzoyltropine and tropacocaine on several cholinergic processes in the rat brain.[Pubmed:1974643]

J Pharmacol Exp Ther. 1990 Aug;254(2):584-90.

Benzoyltropine and Tropacocaine are two contaminants of street-cocaine reported to have parasympatholytic activity. Because the mechanism underlying this activity is obscure, we investigated the effects of these compounds on several cholinergic processes: sodium-dependent choline uptake, sodium-independent choline uptake, acetylcholine synthesis, acetylcholine release (spontaneous and veratridine-induced) and binding of [3H]quinuclidinyl benzylate to muscarinic receptors. These studies used rat cerebral cortical synaptosomes, except for the receptor-binding studies, which used whole brain plasma membranes. Benzoyltropine and Tropacocaine each inhibited sodium-dependent choline uptake and acetylcholine synthesis in a dose-related manner that was competitive with extracellular choline. Benzoyltropine was 4 to 5 times more potent in both actions than Tropacocaine. Sodium-independent choline uptake was not affected by either compound. Benzoyltropine (30 microM) had no effect on the sodium-dependent uptake of norepinephrine, gamma-amino-butyric acid, glutamate or serotonin; Tropacocaine (30 microM) inhibited only norepinephrine uptake at this concentration. Benzoyltropine and Tropacocaine each inhibited the spontaneous and veratridine-induced release of newly synthesized acetylcholine, but not via activation of presynaptic muscarinic receptors. Instead, each compound was able to attenuate the oxotremorine-induced inhibition of the release of acetylcholine, suggesting antimuscarinic activity. Binding experiments showed that benzoyltropine and Tropacocaine were, respectively, about 1,000- and 10,000-fold less potent than scopolamine as receptor antagonists. Finally, we demonstrated that benzoyltropine accumulates in the rat brain after its peripheral injection (10 mg/kg i.p.) and remains there with a half-life similar to that of cocaine.(ABSTRACT TRUNCATED AT 250 WORDS)