Modulation of cholinergic contractions of airway smooth muscle by cathinone: potential beneficial effects in airway diseases

Natural Sympathomimetic Drugs: From Pharmacology to Toxicology

Sympathomimetic agents are a group of chemical compounds that are able to activate the sympathetic nervous system either directly via adrenergic receptors or indirectly by increasing endogenous catecholamine levels or mimicking their intracellular signaling pathways. Compounds from this group, both used therapeutically or abused, comprise endogenous catecholamines (such as adrenaline and noradrenaline), synthetic amines (e.g., isoproterenol and dobutamine), trace amines (e.g., tyramine, tryptamine, histamine and octopamine), illicit drugs (e.g., ephedrine, cathinone, and cocaine), or even caffeine and synephrine. In addition to the effects triggered by stimulation of the sympathetic system, the discovery of trace amine associated receptors (TAARs) in humans brought new insights about their sympathomimetic pharmacology and toxicology. Although synthetic sympathomimetic agents are mostly seen as toxic, natural sympathomimetic agents are considered more complacently in the terms of safety in the vision of the lay public. Here, we aim to discuss the pharmacological and mainly toxicological aspects related to sympathomimetic natural agents, in particular of trace amines, compounds derived from plants like ephedra and khat, and finally cocaine. The main purpose of this review is to give a scientific and updated view of those agents and serve as a reminder on the safety issues of natural sympathomimetic agents most used in the community.

Impact of chronic khat (Catha edulis Forsk) chewing on pulmonary function test and oxygen saturation in humans: A comparative study

Background:

Chronic consumption of khat affects many organ systems and leads to various health disturbances in the chewers. Few studies examined the acute effects of khat ingestion on lung function parameters. However, studies which assessed the long-term effects of khat chewing on pulmonary function parameters and oxygen saturation are lacking.

Objective:

The aim of this study was to assess the impact of chronic Khat chewing on pulmonary function parameters and oxygen saturation among chronic Khat chewers in Wolkite, Ethiopia.

Methods:

A community-based comparative cross-sectional study was conducted in Wolkite, Ethiopia from 1 June 2018 to 15 August 2018. A total of 324 participants, 162 khat chewers and 162 non-chewers were included in the study. The data were collected through face-to-face interview by trained data collectors. British Medical Research Council respiratory questionnaire was used to assess respiratory symptoms. A spirometer was used to assess various lung function parameters. Moreover, oxygen saturation of hemoglobin was measured using pulse oximeter. Data were entered into CSPro version 6.2 and analyzed using SPSS version 23.

Results:

This study showed statistically significant (p < 0.05) reduction in the mean values of forced vital capacity, forced expiratory volume in first second and maximum ventilation volume among khat chewers as compared to non-chewers. There was no significant difference in the mean values of other lung function parameters between the two groups. Similarly, there was no significant difference (p = 0.642) in mean oxygen saturation of hemoglobin (SaO₂) across the two groups.

Conclusion:

It is evident from this study that long-term khat consumption is associated with decreased mean forced vital capacity, forced expiratory volume in first second and maximum ventilation volume. Hence, there is a need for further study to strengthen the current findings and to explore the mechanisms of khat chewing effect on lung function parameters.

Gender differences in the effects of cathinone and the interaction with caffeine on temperature and locomotor activity in the rat

We have investigated gender differences in the effects of cathinone and the interaction with caffeine on temperature and movement activity in Wistar rats. Telemetry probes were implanted in rats under isoflurane anaesthesia, and 7 days later, temperature and activity were recorded in conscious unrestrained animals. Caffeine (10mg/lkg) or vehicle, and 30min later, cathinone (5mg/kg) or vehicle, were injected subcutaneously. Cathinone produced significant and marked increases in activity, and the response to cathinone was significantly greater in female animals. The combination of caffeine and cathinone causes a short lived potentiation followed by a prolonged inhibition of the activity response to cathinone. Cathinone alone had minor effects on temperature. However, the combination of caffeine and cathinone produced a significant acute rise in temperature only in male rats in the 90min after cathinone injection. Hence, cathinone caused greater increases in activity in female than in male rats. Secondly, caffeine produced an initial potentiation followed by a prolonged inhibition of the activity response to cathinone. Thirdly, cathinone in combination with caffeine significantly raised temperature acutely in male but not female rats. These differences highlight the need to carry out gender studies of the actions of stimulants.

Sensitive hydrophilic interaction liquid chromatography/tandem mass spectrometry method for rapid detection, quantification and confirmation of cathinone-derived designer drugs for doping control in equine plasma

RATIONALE

Cathinone derivatives are new amphetamine-like stimulants that can evade detection when presently available methods are used for doping control. To prevent misuse of these banned substances in racehorses, development of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method became the impetus for undertaking this study.

METHODS

Analytes were recovered via liquid-liquid extraction using methyl tert-butyl ether. Analyte separation was achieved on a hydrophilic interaction column using liquid chromatography and mass analysis was performed on a QTRAP mass spectrometer in positive electrospray ionization (ESI) mode with multiple reaction monitoring (MRM). Analyte identification was carried out by screening for a specified MRM transition. Quantification was conducted using an internal standard. Confirmation was performed by establishing a match in retention time and ion intensity ratios comparison.

RESULTS

The method was linear over the range 0.2-50 ng/mL. The specificity was evaluated by analysis of six different batches of blank plasma and those spiked with each analyte (0.2 ng/mL). The recovery of analytes from plasma at three different concentrations was >70%. The limits of detection, quantification and confirmation were 0.02-0.05, 0.2-1.0 and 0.2-10 ng/mL, respectively. The matrix effect was insignificant. The intra-day and inter-day precision were 1.94-12.08 and 2.58-13.32%, respectively.

CONCLUSIONS

The method is routinely employed in screening for the eleven analytes in post-competition samples collected from racehorses in Pennsylvania to enforce the ban on the use of these performance-enhancing agents in racehorses. The method is sensitive, fast, effective and reliably reproducible.

Correlates of nicotine dependence in U.K. resident Yemeni khat chewers: a cross-sectional study

INTRODUCTION

Khat chewing is often associated with tobacco use with impacts on health. This cross-sectional study aimed (a) to explore and validate aspects of self-reported tobacco smoking and whether objective measures of tobacco smoking differ in different situations among khat chewers who smoked and (b) to assess the social factors correlated with nicotine dependence among khat chewers who smoked regularly.

METHODS

This study recruited a purposive sample of 204 U.K. resident Yemeni khat chewers during random visits to Khat sale outlets. Data were collected via a face-to-face scheduled interview. Data analyses included descriptive tests and a hierarchical linear multiple regression.

RESULTS

Of 133 self-reported tobacco smokers, 68% were regular smokers with a mean (SD) carbon monoxide (CO) score (20.53 ± 12.12 ppm) and 32% were episodic smokers with a mean (SD) CO score (16 ± 15.66 ppm). Tobacco smoking as an enhancement of the impacts of khat chewing was reported by 65% and 69% of regular and episodic smokers, respectively. In both groups, higher CO scores were recorded during khat chewing. Hierarchical linear multiple regression modeling showed that increases in levels of severity of dependence on khat chewing were correlated positively with increase in levels of nicotine dependence (β = .27, p = .006, 95% CI = 0.05, 0.29), whereas social participation was correlated inversely (β = -.34, p = .001, 95% CI = -0.06, -0.02).

CONCLUSIONS

In this study, smoking prevalence was high. Smoking increased during khat chewing. Nicotine dependence levels correlated positively with khat dependence levels, while higher social participation reduced nicotine dependence.

Validity and reliability of a Severity of Dependence Scale for khat (SDS-khat)

AIMS OF THE STUDY

(1) To assess psychological khat dependence and (2) to assess the validity and reliability of the Severity Dependence Scale (Gossop et al., 1995) amended for khat use (SDS-khat), in a sample of UK-resident male adult Yemeni khat chewers.

MATERIALS AND METHODS

A cross-sectional study using a face to face structured interview schedule was conducted amongst purposively sampled UK-resident adult Yemeni male khat chewers, aged 18 years and above, selected during random visits to places of khat sale. A factor analysis with principal components extraction was conducted to explore the construct validity of the proposed SDS-khat. Reliability of the proposed scale was assessed using test-retest and internal reliability tests. The concurrent validity of the proposed SDS-khat was assessed in relation to individual measures and a composite index of khat chewing behaviours using univariate analyses.

RESULTS

Two hundred and four Yemeni male adult khat chewers were interviewed. The mean score of the proposed SDS-khat was 5.52 (SD ±4.03). Forty nine percent of respondents (95% CI=43-55%) with ≤5 scores were more likely not psychologically dependent. A single factor, uni-dimensional solution identifying the five items making up the scale accounted for 52.33% of variance. The internal reliability was good (Cronbach's alpha coefficient=0.76) and the test retest intraclass correlation coefficient (ICC) was 0.93 (95% CI=0.80-0.97). Many individual aspects of the khat chewing were significantly related to the scale. Assessment of the proposed SDS-khat's concurrent validity with individual items of khat chewing identified several significant relationships (p≤0.05) whilst the composite index of khat behaviour also identified a significant relationship (OR=14.40, 95% CI=6.71-30.89). The proposed SDS-khat also correlated with self-reported reasons for khat chewing (p≤0.001, OR=3.54; 95% CI=1.80-6.96).

CONCLUSIONS

In this sample of Yemeni khat chewers the SDS-khat is recommended as a valid and reliable research tool for measuring psychological dependence upon khat. Further validation in other samples is indicated.

Khat chewing, cardiovascular diseases and other internal medical problems: the current situation and directions for future research

The leaves of khat (Catha edulis Forsk.) are chewed as a social habit for the central stimulant action of their cathinone content. This review summarizes the prevalence of the habit worldwide, the actions, uses, constituents and adverse health effects of khat chewing. There is growing concern about the health hazards of chronic khat chewing and this review concentrates on the adverse effects on health in the peripheral systems of the body, including the cardiovascular system and gastrointestinal tract. Comparisons are made with amphetamine and ecstasy in particular on the detrimental effects on the cardiovascular system. The underlying mechanisms of action of khat and its main constituent, cathinone, on the cardiovascular system are discussed. Links have been proposed between khat chewing and the incidence of myocardial infarction, dilated cardiomyopathy, vascular disease such as hypertension, cerebrovascular ischaemia and thromboembolism, diabetes, sexual dysfunction, duodenal ulcer and hepatitis. The evidence, however, is often based on limited numbers of case reports and only few prospective controlled studies have been undertaken. There is therefore an urgent need for more thorough case-control studies to be performed. This review outlines the current knowledge on the adverse health effects of khat chewing on the cardiovascular system and other internal medical problems, it assesses the evidence and the limitations of the studies and identifies the questions that future studies should address.