Role of spinal 5-HT5A, and 5-HT1A/1B/1D, receptors in neuropathic pain induced by spinal nerve ligation in rats

Neuropathic Pain: Central vs. Peripheral Mechanisms

“…Electrical stimulation of the thalamus causes spinal serotonin (5-HT) release that relieves neuropathic pain [106], consistent with the observation that intrathecal injection of serotonin can reverse allodynia [107]. The somatosensory cortex is also involved in descending anti-nociception through reducing "on" cell discharge in the rostral ventromedial medulla (RVM) in a 5-HT 1A receptor-dependent fashion [108].…”

Antiallodynic effect induced by [6]‐gingerol in neuropathic rats is mediated by activation of the serotoninergic system and the nitric oxide–cyclic guanosine monophosphate–adenosine triphosphate‐sensitive K+ channel pathway

“…It should be noted that 5‐HT, in terms of its role in pain modulation, initially appears complex because of the myriad of spinal cord receptors that it can act upon. There is evidence that the intrathecal administration of exogenous 5‐HT or 5‐carboxamidotryptamine reverses tactile allodynia in spinal nerve‐ligated rats (Avila‐Rojas et al, ). Several studies have demonstrated that activation of spinal 5‐HT 1A/1B (Colpaert et al, ) and 5‐HT 5 (Avila‐Rojas et al, ) receptors reduced the behavioral or electrophysiological measures related to neuropathic pain.…”

“…Additionally, for the serotonergic system, animals were administered with a vehicle (saline solution at 0.9%; n = 6) or nonselective 5‐HT receptor antagonist (methiothepin, 3 and 30 μg per rat; n = 6; de los Monteros‐Zuñiga et al, ) 20 min before the [6]‐gingerol (10 μg per rat) injection, which was given 10 min before the allodynia evaluation. Moreover, with the purpose to investigate the possible involvement of 5‐HT 1A/1B/1D/5A receptor subtypes, we evaluated the selective 5‐HT 1A receptor antagonist (WAY‐100635, 0.6 and 6.0 μg per rat; n = 6; de los Monteros‐Zuñiga et al, ), selective 5‐HT 1B receptor antagonist (SB‐224289, 0.5 and 5.0 μg per rat; n = 6; de los Monteros‐Zuñiga et al, ), selective 5‐HT 1D receptor antagonist (BRL‐15572, 0.4 and 4.0 μg per rat; n = 6; de los Monteros‐Zuñiga et al, ), and the selective 5‐HT 5A receptor antagonist (SB‐699551, 0.6 and 6.0 μg per rat; n = 6; Avila‐Rojas et al, ). Finally, in order to determine the possible participation of the NO–cGMP–ATP‐sensitive K + channel pathway in the [6]‐gingerol‐induced antiallodynic effect, we used the nonselective NO synthase inhibitor (L‐NAME, 10 and 100 μg per rat; n = 6), guanylyl cyclase inhibitor (ODQ, 1 and 10 μg per rat; n = 6), and ATP‐sensitive K + channel blocker (glibenclamide, 5 and 50 μg per rat; n = 6; de los Monteros‐Zuñiga et al, ).…”

Altered transcription of glutamatergic and glycinergic receptors in spinal cord dorsal horn following spinal cord transection is minimally affected by passive exercise of the hindlimbs

“…5‐HT 1A R activation is linked to pain (Avila‐Rojas et al ., ) and in our initial study demonstrated region‐specific distribution with an eightfold higher expression in laminae I‐III compared to laminae VII, VIII and IX. Despite this, no alteration in gene expression was seen for the 5‐HTRs.…”