The parafascicular nucleus (PFN) of thalamus, as a supraspinal structure, has an important role in processing of nociceptive information. In addition, μ-opioid receptor contributes to supraspinal modulation of nociception. In the present study, the effects of microinjection of naloxone (a non-specific opioid-receptor antagonist) and naloxonazine (a specific μ-opioid receptor antagonist) were in...

W-18 (4-chloro-N-[1-[2-(4-nitrophenyl)ethyl]-2-piperidinylidene]-benzenesulfonamide) and W-15 (4-chloro-N-[1-(2-phenylethyl)-2-piperidinylidene]-benzenesulfonamide) represent two emerging drugs of abuse chemically related to the potent opioid agonist fentanyl (N-(1-(2-phenylethyl)-4-piperidinyl)-N-phenylpropanamide). Here, we describe the comprehensive pharmacological profiles of W-18 and W-15,...

σRs have been mischaracterized [2-4] and were initially thought to be opioid receptor subtypes [5]. They have been classified into two subtypes based on specific radioligand binding assays using [3H](+)pentazocine for σ1Rs and [3H]1,3-di-o-tolylguanidine ([3H]DTG), in the presence of (+)-pentazocine to mask the σ1R, for σ2Rs [6-11] (Table 1). The σ1R has already been cloned and is a 25-29 kDa i...

in the present study, the effect of gaba (γ-aminobutyric acid) receptor agonists and antagonists on morphine-induced antinociception was investigated in formalin test in rats. intraperitoneal (i.p.) injection of different doses of morphine (1, 3, 6 and 9 mg/kg) and intracerebroventricular (i.c.v.) injection of different doses of muscimol (0.5, 1 and 2 g/rat) or baclofen (0.25, 0.5 and 1 g/rat) ...

Opioid and opioid-like receptors are activated by a variety of endogenous peptides including [Met]enkephalin (met), [Leu]enkephalin (leu), β-endorphin (β-end), α-neodynorphin, dynorphin A (dynA), B (dynB), big (Big dyn), nociceptin/orphanin FQ (N/OFQ); endomorphin-1 endomorphin-2 also potential peptides. The Greek letter nomenclature for the opioid receptors, μ, δ κ, is well established, NC-IUP...

Opioids are a mainstay in acute pain management and produce their effects side (e.g., tolerance, opioid-use disorder immune suppression) by interaction with opioid receptors. I will discuss pharmacology some controversial areas of enquiry anaesthetic relevance. The main target is the µ (mu,MOP) receptor but other members family, δ (delta; DOP) κ (kappa; KOP) receptors also analgesic actions. Th...

Activation of G protein-coupled receptors (GPCRs) may bring about their disappearance from the cell membrane, and it is commonly accepted that G protein-coupled receptor kinases (GRKs) play a key function in this mechanism. Opioid receptors belong to the family of GPCRs and are substrates of GRKs. We examined the fate of and -opioid receptors and GRK2 and 3 in living cells during the process of...

In the present study, the effect of GABA (γ-aminobutyric acid) receptor agonists and antagonists on morphine-induced antinociception was investigated in formalin test in rats. Intraperitoneal (i.p.) injection of different doses of morphine (1, 3, 6 and 9 mg/kg) and intracerebroventricular (i.c.v.) injection of different doses of muscimol (0.5, 1 and 2 g/rat) or baclofen (0.25, 0.5 and 1 g/rat) ...