Abstract. Nefopam, an analgesic drug, effectively elicits antinociception in the majority of noxious and thermal models in rodents. Acetaminophen is among the most commonly used analgesic and antipyretic drugs worldwide, either on prescription or over the counter. The present study aimed to investigate the analgesic activity of nefopam combined with acetaminophen, which was expected to maximize the potency of analgesia and decrease the dose of nefopam required. Three series of experiments, namely acetic acid-induced writhing tests in mice, hot plate tests in mice and tail flick tests in rats, were used to evaluate the analgesic effect. Initially, an optimum proportion of the two drugs, 3.5 mg/kg nefopam (N) + 60 mg/kg acetaminophen (A), was determined by orthogonal array design based on writhing response number. Subsequently, combinations of N and A (1.75 N + 30 A, 3.5 N + 60 A and 7.0 N + 120 A mg/kg) were determined to elicit antinociception in the writhing test (P<0.01 vs. normal saline control) in a dose-dependent manner. In the hot plate test, hot plate latencies up to 60 min after drug treatment were observed. The combination of 7.0 N + 120 A mg/kg exerted a greater cumulative antinociceptive effect throughout the observation period, with an area under the curve value of 1,156.95±199.30 area units (AU), compared with that achieved by 7.0 N mg/kg alone (632.12±62.38 AU). Furthermore, both monotherapy and compound therapy exhibited antinociception dose-dependently in the tail-flick test. However, a combination of 5.0 N + 84 A mg/kg exerted greater analgesic effect compared with 5.0 N mg/kg alone. The data obtained demonstrate that acetaminophen may enhance the antinociceptive activity of nefopam. Thus, coadministration of nefopam with acetaminophen warrants clinical evaluation.

CB1R played an important part via several signaling pathways in the protection from ischemic stroke and in ischemic tolerance. The involved molecular signaling pathways include ERK1/2, PI3K/Akt/GSK-3β and the translocation and activation of PKCε. With the intimate association between CB1R and neuron injuries, to target the receptor will exert neuroprotective effects on cerebral ischemia, which provides wide foreground for a novel therapy target.

The aim of the present study was to establish an improved method for in vitro guinea pig airway smooth muscle (ASM) cell culture and to evaluate the effect of 2-(4-amino-3-chloro-5-trifluomethyl-phenyl)-2-tert-butylamino-ethanol hydrochloride (SPFF), a novel β2-adrenoceptor agonist, on the release of intracellular calcium in cells. A procedure for the efficient isolation, culture, passage and characterization of the cells was described. Primary ASM cells of guinea pigs were cultured by modified tissue cultivation. The cells were identified by their morphological characteristics and immunocytochemistry. The relative inhibition of the release of intracellular calcium by drugs in the cells was measured by fluorometric quantification with fluorochrome Fura-2/AM. The results were as follows: a) The ASM cells of the guinea pigs were successfully cultured and subcultured by using our improved method and typical peak-valley characteristics were observed under the phase contrast microscope; b) data from immunocytochemical staining with specific α-smooth muscle actin (α-SMA) demonstrated that the cells were ASM cells; c) the growth characteristics and cell viability demonstrated that the cells were in good condition and were able to be applied in the follow-up studies; d) the inhibitory effect of SPFF on the release of intracellular calcium was concentration‑dependent when compared with the control and e) the potential mechanisms of SPFF on the inhibition of intracellular calcium may be independent of the ryanodine receptor, but may be closely associated with the inositol 1,4,5-trisphosphate receptor.

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