The kappa opioid receptor agonist SA14867 has antinociceptive and weak sedative effects in models of acute and chronic pain.

We examined the analgesic effect of the selective kappa opioid receptor agonist SA14867 and the balance of its antinociceptive and sedative effects. The ED(50) values of SA14867 after oral administration for acetic acid-induced writhing, first and second phases of the formalin test, and rotarod test in mice were 6.1, 9.3, 2.7, and 19.5mg/kg, respectively. These values were smaller than those of the conventional kappa receptor agonists asimadoline and U-50488H. However, the balance of the antinociceptive and sedative effects of SA14867 was better than those of the other two drugs. Orally administered SA14867 (0.1-1mg/kg) significantly improved the decreased pain threshold in a specific alternation of rhythm in an environmental temperature (SART)-stressed model by prophylactic and therapeutic treatment. Improvement in the decreased pain threshold of SA14867-treated animals was attenuated by the opioid receptor antagonist naloxone. Furthermore, orally administered asimadoline (10-100mg/kg) improved the decreased pain threshold in a SART-stressed model, but the doses were close to those known to induce sedative effects. In addition, SA14867 (0.1-1mg/kg) significantly inhibited the arthritis-induced decrease in the pain threshold. Subcutaneously administered morphine (0.1-1mg/kg) improved the decreased pain threshold in a SART-stressed model; on the contrary, morphine did not inhibit the arthritis-induced decrease in the pain threshold. Moreover, orally administered SA14867 (0.1-1mg/kg) strongly attenuated mechanical allodynia and thermal hyperalgesia in a sciatic nerve ligation model. These results suggest that SA14867 has analgesic effects on chronic pain and may serve as a new therapeutic agent for pain treatment.

SA14867, a newly synthesized kappa-opioid receptor agonist with antinociceptive and antipruritic effects.

SA14867 ((+)-3-Acetyl-6-chloro-2-[2-(3-(N-(2-ethoxyethyl)-N-isopropylamino)propoxy)-5-methoxyphenyl]benzothiazoline O,O'-diacetyl-L-tartrate), a selective kappa-opioid receptor agonist, was synthesized and its antinociceptive and antipruritic effects were investigated. In a functional binding assay, SA14867 showed approximately more than 31,000 and 2200 fold higher affinity for the kappa-opioid receptor than for the mu- and delta-opioid receptors, respectively. SA14867 inhibited acetic acid-induced writhing and formalin test results after oral administration. The ED(50) values of SA14867 for acetic acid-induced writhing and for formalin test first phase and second phase were 1.9, 9.4, and 6.4 mg/kg, respectively. These values were smaller than those of asimadoline, U-50488H, and tramadol. SA14867 also showed antinociceptive effects in silver nitrate-induced arthritis that were as strong as U-50488H, tramadol, and morphine, and were stronger than asimadoline. The ED(50) value of SA14867 for hyperalgesia of arthritis was approximately 10 mg/kg. In addition, SA14867 showed antipruritic effects on 5-hydroperoxyeicosatetraenoic acid (HPETE) and substance P-induced pruritic models at 1 to 3 mg/kg. SA14867 also attenuated scratching reactions in a morphine-induced pruritic model in monkeys. Some of the inhibitory effects of SA14867 on nociceptive and pruritic models were attenuated by a kappa-opioid receptor antagonist, nor-BNI. These results suggest that SA14867 is a potential antinociceptive and antipruritic drug.

Simplified electroholographic color reconstruction system using graphics processing unit and liquid crystal display projector.

We have constructed a simple color electroholography system that has excellent cost performance. It uses a graphics processing unit (GPU) and a liquid crystal display (LCD) projector. The structure of the GPU is suitable for calculating computer-generated holograms (CGHs). The calculation speed of the GPU is approximately 1,500 times faster than that of a central processing unit. The LCD projector is an inexpensive, high-performance device for displaying CGHs. It has high-definition LCD panels for red, green and blue. Thus, it can be easily used for color electroholography. For a three-dimensional object consisting of 1,000 points, our system succeeded in real-time color holographic reconstruction at rate of 30 frames per second.