The limbic system has been implicated in the modulation of pain. The aim of this study was to determine the role of amygdala in different types of pain, viz., phasic and tonic. Unilateral stimulation of central nucleus of amygdala (CeA), basolateral nucleus (BL) and medial amygdaloid (MeA) in conscious rats resulted in the reduction of the tonic formalin-induced pain. The thresholds for simple ...

This study characterizes the anesthetic profile of dexmedetomidine on the basis of steady-state plasma concentrations using defined stimulus-response, ventilatory, and continuous electroencephalographic (EEG) and cardiovascular effect measures in rats. At constant plasma concentrations of dexmedetomidine (range, 0.5-19 ng/ml), targeted and maintained by target-controlled infusion, the whisker r...

  There are several reports on the therapeutic effects of TFG in Iranian traditional medical literature such as antinociceptive, antipyretic, and anti-inflammatory, antidiabetic and antidiuretic effects. The anti-inflammatory and anti-pyretic effects of TFG have been confirmed in experimental models. In the present study, the antinociceptive effect of TFG extract in formalin and tail flick test...

Recent neuroanatomical and behavioral evidence has indicated that vasopressin (VA) increases pain threshold. The dorsal raphe nucleus (DRN) is an important nucleus in pain modulation. Anatomical studies have shown that DRN receives vasopressinergic fibers originating in the hypothalamic paraventricular nucleus. The aim of the present study was to examine the effects of intra-DRN injection of de...

The current study has investigated the involvement of periaqueductal gray (PAG) metabotropic glutamate subtype 7 and 8 receptors (mGluR(7) and mGluR(8)) in modulating rostral ventromedial medulla (RVM) ongoing and tail flick-related on and off cell activities. Our study has also investigated the role of PAG mGluR(7) on thermoceptive threshold and PAG glutamate and GABA release. Intra-ventrolate...

The leaves of Mitragyna speciosa were chewed as a substitute to opium in Thailand and Malaysia. A study was therefore undertaken to compare the antinociceptive activity of morphine and paracetamol to that of mitragynine, a major constituent of fresh leaves of M. speciosa. The tests employed were acetic acid induced writhings, hot tail-flick and cold tail flick. All test drugs were administered ...

bulbospinal noradrenergic pathways are shown to have an important role in descending inhibition of pain sensation. locus ceruleus (lc), as a rich noradrenergic nucleus in the brain stem which has projections into the dorsal horn of the spinal cord, was evaluated for antinociceptive activity by using tonic and phasic pain models in the rat. lc-lesioned rats demonstrated moderate increase in both...

This study investigated the antinociceptive mechanisms of khat extract (100, 200, and 400 mg/kg, i.p.) in four pain models: two thermic (hot plate, tail-flick) and two chemical (acetic acid, formalin) models. Male mice were pretreated intraperitoneally (i.p.) with the opioid receptor blocker naloxone (5 mg/kg), the cholinergic antagonist atropine (2 mg/kg), the selective α1 blocker prazosin (1 ...

The present study aims to investigate the analgesic activity of the methanol extract of the galls of Quercus infectoria in rats using hot plate and tail-flick methods. The extract was administered intraperitoneally at a dose of 20 mg/kg while morphine sulfate and sodium salicylate (10 mg/kg) served as standards. The methanol extract exhibited significant analgesic activity in the tail-flick mod...