کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2494732 1115577 2008 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Removing TRPV1-expressing primary afferent neurons potentiates the spinal analgesic effect of δ-opioid agonists on mechano-nociception
موضوعات مرتبط
علوم زیستی و بیوفناوری علم عصب شناسی علوم اعصاب رفتاری
پیش نمایش صفحه اول مقاله
Removing TRPV1-expressing primary afferent neurons potentiates the spinal analgesic effect of δ-opioid agonists on mechano-nociception
چکیده انگلیسی

Most δ-opioid receptors are located on the presynaptic terminals of primary afferent neurons in the spinal cord. However, their presence in different phenotypes of primary afferent neurons and their contribution to the analgesic effect of δ-opioid agonists are not fully known. Resiniferatoxin (RTX) is an ultra-potent transient receptor potential vanilloid type 1 channel (TRPV1) agonist and can selectively remove TRPV1-expressing primary afferent neurons. In this study, we determined the role of δ-opioid receptors expressed on TRPV1 sensory neurons in the antinociceptive effect of the δ-opioid receptor agonists [d-Pen2,d-Pen5]-enkephalin and [d-Ala2,Glu4]-deltorphin. Nociception was measured by testing the mechanical withdrawal threshold in the hindpaw of rats. Changes in the δ-opioid receptors were assessed using immunocytochemistry and the [3H]-naltrindole radioligand binding. In RTX-treated rats, the δ-opioid receptor on TRPV1-immunoreactive dorsal root ganglion neurons and afferent terminals in the spinal cord was diminished. RTX treatment also significantly reduced the maximal specific binding sites (31%) of the δ-opioid receptors in the dorsal spinal cord. Interestingly, intrathecal injection of [d-Pen2,d-Pen5]-enkephalin or [d-Ala2,Glu4]-deltorphin produced a large and prolonged increase in the nociceptive threshold in RTX-treated rats. These findings indicate that loss of TRPV1-expressing afferent neurons leads to a substantial reduction in presynaptic δ-opioid receptors in the spinal dorsal horn. However, the effect of δ-opioid agonists on mechano-nociception is paradoxically potentiated in the absence of TRPV1-expressing sensory neurons. This information is important to our understanding of the cellular sites and mechanisms underlying the spinal analgesic effect of δ-opioid agonists.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neuropharmacology - Volume 55, Issue 2, August 2008, Pages 215–222
نویسندگان
, ,