Effect of atropine sulfate on gastric emptying and gastrocecal transit time evaluated by using the [1-(13)C]acetic acid and lactose-[(13)C]ureide breath test in conscious rats

Acute exercise inhibits gastric emptying of liquids in rats: influence of the NO-cGMP pathway

We previously found that acute exercise inhibited the gastric emptying of liquid in awake rats by causing an acid-base imbalance. In the present study, we investigated the involvement of the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway, vasoactive intestinal peptide (VIP), and corticotropin-releasing factor (CRF) peptide in this phenomenon. Male rats were divided into exercise or sedentary group and were subjected to a 15-min swim session against a load (2.5 or 5% b.w.). The rate of gastric emptying was evaluated after 5, 10, or 20 min postprandially. Separate groups of rats were treated with vehicle (0.9% NaCl, 0.1 mL/100 g, ip) or one of the following agents: atropine (1.0 mg/kg, ip), the NO non-selective inhibitor Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME; 10.0 mg/kg, ip), or the selective cGMP inhibitor 1H-(1,2,4)oxadiazole[4,3-a]quinoxalin-1-one (ODQ; 5.0 mg/kg, ip), the i-NOS non-specific inhibitor (aminoguanidine; 10.0 mg/kg, ip), the corticotropin-releasing factor receptor antagonist (astressin; 100 µg/kg, ip), or the vasoactive intestinal peptide (VIP) receptor antagonist Lys¹, Pro^2,5, Arg^3,4, Tyr⁶ (100 µg/kg, ip). Compared to sedentary rats, both the 2.5 and 5% exercise groups exhibited higher (P<0.05) values of blood lactate and fractional gastric dye recovery. Corticosterone and NO levels increased (P<0.05) in the 5% exercised rats. Pretreatment with astressin, VIP antagonist, atropine, L-NAME, and ODQ prevented the increase in gastric retention caused by exercise in rats. Acute exercise increased gastric retention, a phenomenon that appears to be mediated by the NO-cGMP pathway, CRF, and VIP receptors.

Exploring new pharmacology and toxicological screening and safety evaluation of one widely used formulation of Nidrakar Bati from South Asia region

BACKGROUND

Nidrakar Bati (NKB) is an herbal remedy consisted with seven medicinal herbs widely used to cure Somnifacient (sleeping aid) in South Asia as Ayurvedic medicinal system. In the present study, pharmacological and toxicological effects of this medicine was investigated in mice to validate the safety and efficacy of the herb.

METHODS

Organic solvent extracts NKB were prepared using maceration method. Effect of extracts on the central nervous system was evaluated using hypnotic activity assay. Effect of the extracts on metabolic activity, assessing involvement of thyroid was conducted using hypoxia test. analgesic and anti-inflammatory activities were assessed in mice using acetic acid induced writhing, formalin induced paw edema, xylene induced ear edema assays. Anxiolytic activity was performed using plus maze, climbing out and forced swimming tests. Effect of the extracts on psychopharmacological effect was carried out using locomotor activity tests (open field, Hole-board and Hole-cross tests). Neuropharmacological effect of the extracts was performed using motor coordination (rotarod test). Toxicological potential of the extract was evaluated using gastro-intestinal activity (gastric emptying and gastrointestinal motility tests).

RESULTS

The studied formulation reduced the CNS stimulant effects dose independently. In the hypoxia test, only a dose of 100 mg/kg of NKB decreased the survival time. Orally administration of the NKB (200 and 400 mg/kg) produced significant inhibition (P < 0.01) of the acetic acid-induced writhing in mice and suppressed xylene induced ear edema and formalin-induced licking response of animals in both phases of the test. NKB showed locomotor activity (p < 0.05) both in higher and lower doses (100 and 400 mg/kg). NKB increased the total ambulation dose dependently (p < 0.05). NKB, at all tested doses (100, 200 and 400 mg/kg) increased some locomotion activity parameters (ambulation, head dipping and emotional defecation) in hole board test. At higher doses (200 and 400 mg/kg), NKB showed a significant increase in hole cross test. NKB showed an increase in the time on the open arms of the maze at low to medium doses (100 and 200 mg/kg). When using the Rotarod method, NKB showed a considerable increase on motor coordination of the mice. NKB produced marked gastric emptying effect and decreased gastrointestinal motility in mice at low dose.

CONCLUSIONS

NKB demonstrated various pharmacological effects and toxicological effects due to presence of several herbs in the formulation those are not closely fit for the effect of CNS depressants.