Central H2 histaminergic and alpha-2 adrenergic receptors involvement in crocetin-induced antinociception in orofacial formalin pain in rats

Effect of thymoquinone on acetic acid-induced visceral nociception in rats: role of central cannabinoid and α2-adrenergic receptors

Thymoquinone (TQ) is the main biologically active substance of Nigella sativa (black seeds). It has anti-cancer, anti-inflammatory, anti-diabetic, anti-oxidative and anti-nociceptive properties. This study was aimed to explore the effect of TQ on acetic acid-induced visceral nociception. The central mechanisms of the effect of TQ were investigated using cannabinergic (AM251) and α2-adrenergic (yohimbine [Yoh]) antagonists. The lateral ventricle of the brain was cannulated for intracerebroventricular (ICV) injections. Visceral nociception was induced by intra-peritoneal (IP) injection of acetic acid (1.00% in a volume of 1.00 mL). Measuring the latency time to the first writhing appearance and counting the number of writhing in 5-min intervals for a period of 60 min were performed. Locomotor activity was determined using an open-field test. Oral administration (PO) of 2.50 and 10.00 mg kg-1 TQ increased the latency time to the first writhing appearance and decreased the number of writhing. The AM251 (5.00 µg per rat; ICV) and Yoh (5.00 µg per rat; ICV) partially prevented TQ (10.00 mg kg-1; PO)-induced anti-nociception. Locomotor activity was not altered by these treatments. The results of the present study showed that TQ had the ability to reduce visceral nociception caused by IP injection of acetic acid. The central mechanisms of this action of TQ might be partially mediated by cannabinergic and α2-adrenegic receptors.

Carotenoids in Palliative Care—Is There Any Benefit from Carotenoid Supplementation in the Adjuvant Treatment of Cancer-Related Symptoms?

Carotenoids are organic, liposoluble pigments found in nature, which are responsible for the characteristic colors of ripe tomatoes, carrots, peppers, and crustaceans, among others. Palliative care provided to patients with an incurable disease is aimed at improving the patient’s quality of life through appropriate treatment of symptoms accompanying the disease. Palliative care patients with burdensome symptoms related to advanced-stage cancers are especially interested in the use of natural dietary supplements and herbal remedies to reduce symptoms’ intensity and ameliorate the quality of life. Carotenoids seem to be a group of natural compounds with particularly promising properties in relieving symptoms, mainly due to their strong antioxidant, anti-inflammatory, and neuroprotective properties. Moreover, carotenoids have been used in folk medicine to treat various diseases and alleviate the accompanying symptoms. In this narrative review, the authors decided to determine whether there is any scientific evidence supporting the rationale for carotenoid supplementation in advanced-stage cancer patients, with particular emphasis on the adjuvant treatment of cancer-related symptoms, such as neuropathic pain and cancer-related cachexia.

Crocetin: A Systematic Review

Crocetin is an aglycone of crocin naturally occurring in saffron and produced in biological systems by hydrolysis of crocin as a bioactive metabolite. It is known to exist in several medicinal plants, the desiccative ripe fruit of the cape jasmine belonging to the Rubiaceae family, and stigmas of the saffron plant of the Iridaceae family. According to modern pharmacological investigations, crocetin possesses cardioprotective, hepatoprotective, neuroprotective, antidepressant, antiviral, anticancer, atherosclerotic, antidiabetic, and memory-enhancing properties. Although poor bioavailability hinders therapeutic applications, derivatization and formulation preparation technologies have broadened the application prospects for crocetin. To promote the research and development of crocetin, we summarized the distribution, preparation and production, total synthesis and derivatization technology, pharmacological activity, pharmacokinetics, drug safety, drug formulations, and preparation of crocetin.

Correlation of Histamine Receptors and Adrenergic Receptor in Broilers Appetite

The current study was conducted to investigate the interaction between the central adrenergic and histaminergic systems and the broiler chick's feed intake. In the first experiment, the intracerebroventricular (ICV) injection of solutions was conducted which included 10 nmol of prazosin (an α₁-receptor antagonist), 300 nmol of histamine, co-injection of prazosin and histamine. Experiments two to five were conducted similarly the same as the first experiment, in which chickens were ICV injected with 13 nmol of yohimbine (an α₂-receptor antagonist), 24 nmol of metoprolol (a β₁ adrenergic receptor antagonist), 5 nmol of ICI 118,551 (a β₂ adrenergic receptor antagonist), and 20 nmol of SR 59230R (a β₃ adrenergic receptor antagonist). The injected solutions in the sixth experiment included 300 nmol of noradrenaline, 250 nmol of α-FMH (an alpha fluoromethyl histidine), noradrenaline, and α-FMH. Seventh to ninth experiments were similar to the sixth experiment, except that the chickens were ICV injected with 300 nmol of chlorpheniramine (a histamine H₁ receptors antagonist), 82 nmol of famotidine (a histamine H₂ receptors antagonist), and 300 nmol of thioperamide (a histamine H₃ receptors antagonist), rather than α-FMH. Afterward, the cumulative food intake was measured 120 min after injection. Based on the obtained results, both histamine ICV injection and noradrenaline injection reduced food intake (P<0.05). Moreover, co-injection of histamine and ICI 118,551 (P<0.05), and co-injection of noradrenaline and Chlorpheniramine reduced food intake (P<0.05). In addition, noradrenaline and Thioperamide co-injection improved hypophagic effect of noradrenaline in neonatal chicken (P<0.05). These findings suggested the effect of interconnection between adrenergic and histaminergic systems, which may be mediated by H₁ and H₃ histaminergic and β₂ adrenergic receptors, on the regulation of food intake in the neonatal broiler chicken.