Arecoline hydrobromide

Arecoline is a natural alkaloid that is found in the betel nut of the Areca palm. It is an agonist of the muscarinic acetylcholine receptors with EC50 values of 7, 95, 11, 410, and 69 nM for M1, M2, M3, M4, and M5, respectively. Generally, arecoline causes smooth muscle contraction. Arecoline and other muscarinic receptor agonists have been shown to improve learning and memory and may prove to be useful in treating dementia

Evaluation of arecoline hydrobromide toxicity after a 14-day repeated oral administration in Wistar rats.[Pubmed:25880067]

PLoS One. 2015 Apr 16;10(4):e0120165.

A subchronic toxicity test was conducted in rats on the basis of a previous acute toxicity test to evaluate the safety of Arecoline hydrobromide (Ah), to systematically study its pharmacological effects and to provide experimental support for a safe clinical dose. Eighty rats were randomly divided into four groups: a high-dose group (1000 mg/kg), medium-dose group (200 mg/kg), low-dose group (100mg/kg) and blank control group. The doses were administered daily via gastric lavage for 14 consecutive days. There were no significant differences in the low-dose Ah group compared to the control group (P>0.05) with regard to body weight, organ coefficients, hematological parameters and histopathological changes. The high-dose of Ah influenced some of these parameters, which requires further study. The results of this study indicated that a long-term, continuous high dose of Ah was toxic. However, it is safe to use Ah according to the clinically recommended dosing parameters. The level of Ah at which no adverse effects were observed was 100 mg/kg/day under the present study conditions.

A protective role of arecoline hydrobromide in experimentally induced male diabetic rats.[Pubmed:25695047]

Biomed Res Int. 2015;2015:136738.

OBJECTIVES: Arecoline, the most potent and abundant alkaloid of betel nut, causes elevation of serum testosterone and androgen receptor expression in rat prostate, in addition to increase in serum insulin levels in rats, leading to insulin resistance and type 2 diabetes-like conditions. This study investigated the role of arecoline on the reproductive status of experimentally induced type 1 diabetic rats. METHODS: Changes in the cellular architecture were analyzed by transmission electron microscopy. Blood glucose, serum insulin, testosterone, FSH, and LH were assayed. Fructose content of the coagulating gland and sialic acid content of the seminal vesicles were also analyzed. RESULTS: Arecoline treatment for 10 days at a dose of 10 mg/kg of body weight markedly facilitated beta-cell regeneration and reversed testicular and sex accessory dysfunctions by increasing the levels of serum insulin and gonadotropins in type 1 diabetic rats. Critical genes related to beta-cell regeneration, such as pancreatic and duodenal homeobox 1 (pdx-1) and glucose transporter 2 (GLUT-2), were found to be activated by arecoline at the protein level. CONCLUSION: It can thus be suggested that arecoline is effective in ameliorating the detrimental effects caused by insulin deficiency on gonadal and male sex accessories in rats with type 1 diabetes.

Frequency- and state-dependent blockade of human ether-a-go-go-related gene K+ channel by arecoline hydrobromide.[Pubmed:22613533]

Chin Med J (Engl). 2012 Mar;125(6):1068-75.

BACKGROUND: The rapidly activating delayed rectifier potassium current (I(Kr)), whose pore-forming alpha subunit is encoded by the human ether-a-go-go-related gene (hERG), is a key contributor to the third phase of action potential repolarization. The aim of this study was to investigate the effect and mechanism of Arecoline hydrobromide induced inhibition of hERG K(+) current (I(hERG)). METHODS: Transient transfection of hERG channel cDNA plasmid pcDNA3.1 into the cultured HEK293 cells was performed using Lipofectamine. A standard whole-cell patch-clamp technique was used to record the I(hERG) before and after the exposure to arecoline. RESULTS: Arecoline decreased the amplitude and the density of the I(hERG) in a concentration-dependent manner (IC(50) = 9.55 mmol/L). At test potential of +60 mV, the magnitude of I(hERG) tail at test pulse of -40 mV was reduced from (151.7 +/- 6.2) pA/pF to (84.4 +/- 7.6) pA/pF (P < 0.01, n = 20) and the magnitude of I(hERG) tail at test pulse of -110 mV was reduced from (-187.5 +/- 9.8) pA/pF to (-97.6 +/- 12.6) pA/pF (P < 0.01, n = 20). The blockade of arecoline in the open and inactivated state was significant in a state-dependent manner. The maximal blockade was achieved in the inactivated state. Studies of gating mechanism showed that the steady-state activation curve of I(hERG) was significantly negatively shifted by arecoline. Time constants of activation were shortened. Steady-state inactivation curve and time constants of fast inactivation were not significantly affected by arecoline. Furthermore, the inhibition of I(hERG) by arecoline was characterized markedly by a frequency-dependent manner from 0.03 to 1.00 Hz pulse. CONCLUSION: Arecoline could potently block I(hERG) in both frequency and state-dependent manner.