Pharmacology, biochemistry, and behavior
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Pharmacol. Biochem. Behav. · Sep 2014
Chronic activation of sigma-1 receptor evokes nociceptive activation of trigeminal nucleus caudalis in rats.
Primary headache disorders, including migraine, are thought to be mediated by prolonged nociceptive activation of the trigeminal nucleus caudalis (TNC), but the precise mechanisms are poorly understood. Our past studies demonstrated that sigma-1 receptors (Sig-1R) facilitate spinal nociceptive transmission in several pain models. Based on these findings, this study asked if chronic activation of Sig-1R by intracisternal administration of the selective Sig-1R agonist, PRE084, produced TNC neuronal activation as a migraine trigger in rats. ⋯ Following 14 days of PRE084 infusion, the number of Fos-IR increased until day 7 after final infusion. Moreover, by day 14, Fos-IR associated with PRE084 infusion was significantly reversed by NMDA receptor antagonist MK801, rather than BD1047. These findings indicated that chronic activation of Sig-1R could evoke prolonged neuronal activation in the trigeminovascular system.
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Pharmacol. Biochem. Behav. · Sep 2014
Interaction between the dopaminergic and opioidergic systems in dorsal hippocampus in modulation of formalin-induced orofacial pain in rats.
The hippocampus is a region of the brain that serves several functions. The dopaminergic system acts through D1- and D2-like receptors to interfere in pain modulation and the opioid receptors play major roles in analgesic processes and there are obvious overlaps between these two systems. The present study investigated the interaction between the opioidergic and dopaminergic systems in the dorsal hippocampus (CA1) region for formalin-induced orofacial pain. ⋯ Sulpiride reversed the antinociceptive effects of morphine only in the first phase, but this result was not significant. Our findings suggest that there is cross-talk between the opioidergic and dopaminergic systems. Opioidergic neurons also exerted antinociceptive effects by modulation of the dopaminergic system in the CA1 region of the brain.
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Pharmacogenetic research has the potential to explain the variation in treatment efficacy within patient populations. Understanding the interaction between genetic variation and medications may provide a method for matching patients to the most effective therapeutic options and improving overall patient outcomes. ⋯ Genetic variants in OPRM1, particularly the non-synonymous polymorphism A118G, have been repeatedly associated with the efficacy of treatments for pain and various types of dependence. This review focuses on the current understanding of the pharmacogenetic impact of OPRM1, primarily with regard to the treatment of pain and addiction.
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Pharmacol. Biochem. Behav. · Jul 2014
Randomized Controlled TrialBaseline-dependent modulating effects of nicotine on voluntary and involuntary attention measured with brain event-related P3 potentials.
Cholinergic stimulation produces cognitive effects that vary across individuals, and stimulus/task conditions. As of yet, the role of individual differences in moderating the effects of the nicotinic acetylcholine receptor agonist nicotine on specific attentional functions and their neural and behavioral correlates is not fully understood. ⋯ Exhibiting an inverted-U nicotine response profile, target P3b and standard N1 amplitudes were increased and decreased in participants with low and high baseline amplitudes, respectively. In all, the findings corroborate the involvement of nicotinic mechanisms in attention, generally acting to increase attentional capacity in relatively low attentional functioning (reduced baseline ERPs) individuals, while having negative or detrimental effects in those with medium/high attentional levels (increased baseline ERPs), and in a manner that is differentially expressed during bottom-up (involuntary) attentional capture and top-down (voluntary) attentional allocation.
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Pharmacol. Biochem. Behav. · Jul 2014
Comparative StudyAntiallodynic and antihyperalgesic activity of 3-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-dihydrofuran-2-one compared to pregabalin in chemotherapy-induced neuropathic pain in mice.
Anticancer drugs - oxaliplatin (OXPT) and paclitaxel (PACLI) cause painful peripheral neuropathy activating Transient Receptor Potential (TRP) channels. Here we investigated the influence of 3-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-dihydrofuran-2-one (LPP1) and pregabalin on nociceptive thresholds in neuropathic pain models elicited by these drugs. Pharmacokinetics of LPP1 and its ability to attenuate neurogenic pain caused by TRP agonists: capsaicin and allyl isothiocyanate (AITC) were also investigated. ⋯ LPP1 and pregabalin reduce pain in OXPT and PACLI-treated mice. This activity of LPP1 might be in part attributed to the inhibition of TRPV1 and TRPA1 channels, but also central mechanisms of action cannot be ruled out.