Meta‐chlorophenylpiperazine attenuates formalin‐induced nociceptive responses through 5‐HT<sub>1/2</sub> receptors in both normal and diabetic mice

Castro-Souza

et al. 1997

Braz J Med Biol Res

The intake of saccharin solutions for relatively long periods of time causes analgesia in rats, as measured in the hot-plate test, an experimental procedure involving supraspinal components. In order to investigate the effects of sweet substance intake on pain modulation using a different model, male albino Wistar rats weighing 180-200 g received either tap water or sucrose solutions (250 g/l) for 1 day or 14 days as their only source of liquid. Each rat consumed an average of 15.6 g sucrose/ day. Their tail withdrawal latencies in the tail-flick test (probably a spinal reflex) were measured immediately before and after this treatment. An analgesia index was calculated from the withdrawal latencies before and after treatment. The indexes (mean ± SEM, N = 12) for the groups receiving tap water for 1 day or 14 days, and sucrose solution for 1 day or 14 days were 0.09 ± 0.04, 0.10 ± 0.05, 0.15 ± 0.08 and 0.49 ± 0.07, respectively. One-way ANOVA indicated a significant difference (F (3, 47) = 9.521, P<0.001) and the Tukey multiple comparison test (P<0.05) showed that the analgesia index of the 14-day sucrose-treated animals differed from all other groups. Naloxone-treated rats (N = 7) receiving sucrose exhibited an analgesia index of 0.20 ± 0.10 while rats receiving only sucrose (N = 7) had an index of 0.68 ± 0.11 (t = 0.254, 10 degrees of freedom, P<0.03). This result indicates that the analgesic effect of sucrose depends on the time during which the solution is consumed and extends the analgesic effects of sweet substance intake, such as saccharin, to a model other than the hot-plate test, with similar results. Endogenous opioids may be involved in the central regulation of the sweet substance-produced analgesia.

mentioning

confidence: 99%

Sucrose ingestion causes opioid analgesia

Castro-Souza

et al. 1997

Braz J Med Biol Res

Journal of Pharmacy and Pharmacology

“…Similar behaviour was observed for the 5-hydroxytryptamine re-uptake inhibitor trazodone, which also potentiated analgesia in conjunction with 5hydroxytryptophan. Trazodone might form 3chlorophenylpiperazine during its biotransformation in-vivo (Caccia & Garattini 1990) and 5hydroxytryptaminergic activity of arylpiperazinyl groups has been established (Fuller et a1 1978;Maj et a1 1979;Kahn & Wetzler 1991;Fontaine 1993;Takeshita & Yamaguchi 1995). These results provide support for the hypothesis that the antinociceptive action of 3 and 4 is partly a central event mediated through 5-hydroxytryptamine.…”

Section: Pharmacological Studiesmentioning

confidence: 77%

Synthesis of Thiazolotriazine Derivatives and Their Antinociceptive Effects in Mice

Issartel¹,

Coudert²,

Rubat³

et al. 1998

Ans raci A series of 2-(4-arylpiperazin-1-yl-methyl)-4-methyl-1-oxo-5,6,8,8a-tetrahydro -thiazolo[3,4-d] [1,2,4]triazines was prepared and tested for antinociceptive activity. The compounds were prepared by the Mannich reaction from the corresponding 2-unsubstituted thiazolotriazines. When administered intraperitoneally most were found to have potent analgesic activity in the mouse during tests of phenylbenzoquinone-induced abdominal constriction; ED50 values (doses resulting in half the maximum effect) ranged from 10 to 87 mg kg(-1). Derivatives with a 3-chloro- or 4-fluorophenylpiperazinylmethyl side-chain in the 2-position of the bicyclic system were, when administered intraperitoneally at doses greater than 25 mg kg(-1), also effective in the hot-plate test without associated sedative effects. The compounds have a large therapeutic index; intraperitoneal LD50 values (doses which result in the death of half the animals) were > 700 mg kg(-1). Naloxone attenuated the analgesic activity of the 3-chloro derivative, suggesting the participation of micro-receptors in the antinociceptive effects of this drug. In addition, a nonopioid mechanism, probably related to enhancement of the release of 5-hydroxytryptamine and noradrenaline, or inhibition of the neuronal re-uptake of these compounds, has been evinced to explain the analgesic properties of the 3-chloro or 4-fluoro derivatives. These results provide evidence for the involvement of noradrenergic and 5-hydroxytryptaminergic pathways in the analgesic activity of 3 and 4. Because of their potential effectiveness, the 3-chloro- or 4-fluorophenylpiperazinylmethyl derivatives might be suitable for treatment of a wide variety of painful conditions and could be attractive reserve agents for patients dissatisfied with opioids.

“…Recent experimental evidence has suggested that insulin has analgesic effects by acting on dopaminergic, and serotonergic analgesic pathways, among others (Anuradha et al., 2004; Dehkordi et al., 2017; Takeshita & Yamaguchi, 1997). In this study, ICV insulin injection produced an analgesic effect in rats.…”

Section: Discussionmentioning

confidence: 99%

The analgesic effects of insulin and its disorders in streptozotocin‐induced short‐term diabetes

Basatinya,

Sajedianfard,

Nazifi

et al. 2024

Physiological Reports

Evidence suggests that insulin resistance plays an important role in developing diabetes complications. The association between insulin resistance and pain perception is less well understood. This study aimed to investigate the effects of peripheral insulin deficiency on pain pathways in the brain. Diabetes was induced in 60 male rats with streptozotocin (STZ). Insulin was injected into the left ventricle of the brain by intracerebroventricular (ICV) injection, then pain was induced by subcutaneous injection of 2.5% formalin. Samples were collected at 4 weeks after STZ injection. Dopamine (DA), serotonin, reactive oxygen species (ROS), and mitochondrial glutathione (mGSH) were measured by ELISA, and gene factors were assessed by RT‐qPCR. In diabetic rats, the levels of DA, serotonin, and mGSH decreased in the nuclei of the thalamus, raphe magnus, and periaqueductal gray, and the levels of ROS increased. In addition, the levels of expression of the neuron‐specific enolase and receptor for advanced glycation end genes increased, but the expression of glial fibrillary acidic protein expression was reduced. These results support the findings that insulin has an analgesic effect in non‐diabetic rats, as demonstrated by the formalin test. ICV injection of insulin reduces pain sensation, but this was not observed in diabetic rats, which may be due to cell damage ameliorated by insulin.