Dose-response inhibitory effects of purified cathinone from khat (Catha edulis) on cortisol and prolactin release in vervet monkeys (Chlorocebus aethiops)

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.

Khat (Catha edulis) upregulates lipolytic genes in white adipose tissue of male obese mice (C57BL/6J)

ETHNOPHARMACOLOGICAL RELEVANCE

Khat (Catha edulis (Vahl) Forssk.) is a herb from the Celastraceae family (also known as qat, gaad, or mirra) that is widely-consumed in East Africa and in the Arabian peninsula. The green leaves and small stems are consumed primarily at recreational and social gatherings, and medicinally for their antidiabetic and appetite-suppression effects.

AIMS

The objectives of this study were to determine the effects of khat and its active alkaloid, cathinone, on food intake and body weight in mice maintained on a high-fat diet, and to investigate its mechanism of action in white adipose tissue and in the hypothalamus.

MATERIALS & METHOD

Adult male mice (C57BL/6J) were fed a high fat diet (HFD) for 8 weeks (n = 30), then divided into 5 groups and treated daily for a further 8 weeks with HFD + vehicle [control (HFD)], HFD + 15 mg/kg orlistat (HFDO), HFD + 200 mg/kg khat extract (HFDK200), HFD + 400 mg/kg khat extract (HFDK400) and HFD + 3.2 mg/kg cathinone (HFDCAT). Treatments were carried out once daily by gastric gavage. Blood and tissue samples were collected for biochemical, hormonal and gene expression analyses.

RESULTS

Khat extracts and orlistat treatment significantly reduced weight gain as compared to control mice on HFD, and cathinone administration completely prevented weight gain in mice fed on HFD. Khat treatment caused a marked reduction in body fat and in serum triglycerides. A dose-dependent effect of khat was observed in reducing serum leptin concentrations. Analysis of gene expression in adipose tissue revealed a significant upregulation of two lipolysis pathway genes:(adipose triglyceride lipase (PNPLA-2) and hormone-sensitive lipase (LIPE). In the hypothalamic there was a significant (P < 0.05) upregulation of agouti-related peptide (AgRP) and cocaine-amphetamine regulated transcript (CART) genes in the HFDK400 and HFDCAT groups.

CONCLUSION

Cathinone treatment blocked body weight gain, while high dose khat extract significantly reduced the weight gain of mice on an obesogenic diet through stimulation of lipolysis in white adipose tissue.

Gonadal and Cortisol Hormone Profile among Male Chronic Khat, Marijuana, and Heroin Abuses

BACKGROUND

Drugs of abuse could interfere with the hypothalamic-pituitary-gonadal axis, causing impaired functions of the gland and associated functions of target organs. Drugs of abuse tend to cause changes in the endocrine system, and these changes could be physiological, molecular, biochemical, genetic, and cellular.

METHOD

A case-control study design was conducted from a total of 171 male consented study participants (148 drug abusers and 23 controls). The serum gonadal and cortisol hormone levels were assayed using the electrochemiluminescence immunoassay method. Socio-demographic variables were collected using a semi-structured questionnaire by the interview method. Nonparametric statistical tools (Mann-Whitney test and median) were used to compare the groups. In all cases, P < 0.05 was considered statistically significant.

RESULT

The median age for drug abusers and control groups was 27, and the age difference between drug abusers and control group was not statistically important. The median estradiol levels among chronic khat chewers (39.4 pg/ml), marijuana (44 pg/mL), and users of heroin (40.2 pg/mL) were significantly higher than control groups (23 pg/mL), P < 0.003. However, the median luteinizing hormone levels among chronic khat chewers (5 IU/L), marijuana users (5 IU/L), and heroin users (5.6 IU/L) were significantly lower than those of control groups (6.2 IU/L), P < 0.02. The median testosterone levels among chronic khat chewers (6.1 ng/mL), marijuana users (6.3 ng/mL), and heroin users (6.6 ng/mL) were significantly lower than control groups (8.0 ng/mL), P < 0.003. However, cortisol and follicle stimulating hormone did not show statistically significant difference between users of khat, marijuana, and heroin compared with the control group.

CONCLUSION

The drug abuser group had significantly lower testosterone and luteinizing hormone levels compared with control groups. Drug abuse has been shown to affect gonadal hormones in an unusual physiological phenomenon. These findings reveal the need for intervention programs to solve these problems.

Anger, anxiety, and depressive affect as predictors of stress-induced cortisol production in khat and tobacco users

INTRODUCTION

Glucocorticoid activity is disrupted in substance users including khat chewers who also use tobacco. Anger, dysphoria, and anxiety can mediate this relationship. The aim of this study was to contrast emotion dysregulation and substance use variables as predictors of post-stress cortisol output.

MATERIALS AND METHODS

Comparable numbers of males (n = 90) and females (n = 85) including controls, khat only, and concurrent khat and tobacco users participated in a stress study. Depressive affect, anxiety, anger, substance use patterns, and saliva samples were collected following a standardized laboratory stress manipulation.

RESULTS

Regression analysis showed that high depression and low anxiety was associated with high post-stress cortisol, but only in co-users of tobacco and khat. Males, but not females, showed a significant association between co-use of khat and tobacco and cortisol, which appears to be mediated by frequency of use. The link between anxiety and post-stress cortisol in the co-users remained significant after controlling for nicotine dependence and substance use frequency.

CONCLUSION

Anxiety predicted the neuroendocrine consequences of concurrent use of tobacco and khat above and beyond sex, nicotine dependence, anger, and substance use frequency. Sex differences, however, are related to differences in nicotine dependence.

Development of the Khat Knowledge, Attitudes and Perception Scale

INTRODUCTION AND AIMS

Khat (Catha edulis) is a stimulant plant widely used in East Africa and the Arabian Peninsula. Tobacco is often co-used with khat and its use has expanded to other parts of the world. Chronic khat use is associated with negative health consequences. There is a lack of research to develop a tool to assess attitudes toward khat use. This study aimed to develop a brief tool to assess attitude and perception related to khat (i.e. the Khat Knowledge, Attitudes and Perception Scale).

DESIGN AND METHODS

Four-hundred and three participants in Yemen (151 concurrent users of khat and tobacco, 141 khat-only users and 92 non-users of khat and tobacco) were asked about knowledge and attitudes related to khat. A principle component analysis with Promax rotation, Scree-plot and Cronbach's α coefficients was performed to examine psychometric properties of the Khat Knowledge, Attitudes and Perception Scale.

RESULTS

Principle component analysis revealed five factors: negative beliefs, positive beliefs, idleness, weight control and family issues. Internal consistency of items in negative beliefs, positive beliefs, idleness, weight control and family issues were 0.88, 0.62, 0.62, 0.72 and 0.53, respectively. Greater negative beliefs was inversely correlated with positive beliefs but positively associated with idleness, weight control and family issues. Concurrent users and khat-only users had lower scores on negative beliefs than non-users. Concurrent users had higher scores on positive beliefs than khat-only and non-users.

DISCUSSION AND CONCLUSIONS

These results provide initial support of the usefulness of the Khat Knowledge, Attitudes and Perception Scale.

Immunohistochemical localization of anterior pituitary cell types of vervet monkey (Chlorocebus aethiops) following sub-chronic cathinone exposure

ETHNOPHARMACOLOGICAL RELEVANCE

Khat (Catha edulis) contains cathinone, an active principal that is customarily used as a psychostimulant that wards off fatigue and to some extent used as an aphrodisiac.

AIM OF STUDY

To investigate effects of escalating doses of cathinone on hormone expression by different anterior pituitary cell types using specific antibodies.

MATERIAL AND METHODS

Eleven vervet monkeys (6 males and 5 females) divided into tests (n=9) and controls (n=2) were used. Animals were allocated as group I (saline controls), group II (0.8 mg/kg), group III (3.2 mg/kg) and group IV (6.4 mg/kg) of cathinone. All treatments were via oral route at alternate days of each week. At the end of 4-month treatment phase, GnRH agonist (ZOLADEX) was administered to group II (low dose) and group IV (high dose) alongside cathinone for 2 additional weeks.

RESULTS

High cathinone dose at long-term exposure caused proliferation of gonadotrophs but decrease in lactotrophs and corticotrophs in anterior pituitary sections of animals while effect of low dose on these cells was insignificant. Subsequent GnRH agonist co-treatment with low and high cathinone doses enhanced gonadotroph proliferation but no change on decline of lactotrophs and corticotrophs.

CONCLUSION

We believe that there was a possible potentiation of cathinone on pituitary hormone synthesis thereby influencing reproductive function. Suppression of corticotrophic and lactotrophic functions suggest lowering of stress levels and modulation of reproductive function based on dose level and chronicity of exposure. The findings are consistent with the hypothesis that cathinone interferes with pituitary cell integrity and consequently target organs, but further studies are required to address the precise mechanism underlying this phenomenon.