BDNF as a pain modulator

At least some neurotrophins may be powerful modulators of synapses, thereby influencing short- and long-term synaptic efficiency. BDNF acts at central synapses in pain pathways both at spinal and supraspinal levels. Neuronal synthesis, subcellular storage/co-storage and release of BDNF at these synapses have been characterized on anatomical and physiological grounds, in parallel with trkB (the high affinity BDNF receptor) distribution. Histological and functional evidence has been provided, mainly from studies on acute slices and intact animals, that BDNF modulates fast excitatory (glutamatergic) and inhibitory (GABAergic/glycinergic) signals, as well as slow peptidergic neurotrasmission in spinal cord. Recent studies have unraveled some of the neuronal circuitries and mechanisms involved, highlighting the key role of synaptic glomeruli in lamina II as the main sites for such a modulation

Metabolic syndrome in human immunodeficiency virus-positive subjects: prevalence, phenotype, and related alterations in arterial structure and function

Background: Human immunodeficiency virus (HIV) infection itself and highly active antiretroviral treatment (HAART) have been proposed to be associated with a higher prevalence of metabolic syndrome, but, to date, prevalence and phenotype of metabolic syndrome among HIV subjects and the related structural and functional vascular alterations are not conclusively defined. Methods: We analyzed the data of 108 HIV-infected subjects without known cardiovascular risk factors: 72 were on HAART (group A, age 46.57.5 years, clinical blood pressure 125.7/74.911.6/7.8mmHg) and there 36 in a naive group (group B, age 40.7 +/- 7.9 years, blood pressure 126/75.8 +/- 9.8/7.7mmHg). A total of 224 healthy subjects served as controls (group C, age 44.9 +/- 6.9 years, blood pressure 123.7/75.7 +/- 9.8/7.1mmHg). Arterial stiffness was measured by aorto-femoral pulse wave velocity (PWV, sfigmocor), and carotid intima media thickness (IMT) was measured by a semiautomatic echotracking system (Esaote-WTS). Results: Metabolic syndrome was more frequent in HIV-positive subjects than in controls (19.4%, 13.8%, 4.5% for groups A, B, and C; P<0.001), with no significant difference between HAART and naive. In metabolic syndrome subjects, group A displayed lipid profile alterations more frequently (91%, 50%, 57% for groups A, B, and C; P<0.05), whereas others metabolic syndrome components were equally represented in the three groups. In metabolic syndrome subjects, IMT was similar [556 +/- 108, 542 +/- 164, and 564 +/- 110.4 m for groups A, B, and C; P=not significant (NS)], whereas PWV was significantly greater in HAART subjects when compared with controls (10.8 +/- 1.8, 9.+/- 1.1, 9.3 +/- 1cm/sec for groups A, B, and C; P=0.02 for A vs. C). Moreover, in this group (metabolic syndrome+HAART), PWV was higher than in subjects on HAART but without metabolic syndrome. Conclusions: HIV subjects showed a higher prevalence and a different pattern of metabolic syndrome components. HAART, more than HIV infection per se, appeared to be responsible for the increased prevalence of metabolic syndrome and arterial function derangement

Delta opioid receptors presynaptically regulate cutaneous mechanosensory neuron input to the spinal cord dorsal horn

Cutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mechanosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mechanoreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated nociceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanoreceptors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cutaneous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity

Delta opioid receptors presynaptically regulate cutaneous mechanosensory neuron input to the spinal cord dorsal horn.

Cutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mechanosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mechanoreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated nociceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanoreceptors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cutaneous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity

Delta Opioid Receptors Presynaptically Regulate Cutaneous Mechanosensory Neuron Input to the Spinal Cord Dorsal Horn.

SummaryCutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mechanosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mechanoreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated nociceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanoreceptors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cutaneous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity

Article Delta Opioid Receptors Presynaptically Regulate Cutaneous Mechanosensory Neuron Input to the Spinal Cord Dorsal Horn

International audienceCutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mecha-nosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mecha-noreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated noci-ceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanorecep-tors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cuta-neous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity