Intrinsic connections within the pedunculopontine tegmental nucleus are critical to the elaboration of post-ictal antinociception.
This study investigated the intrinsic connections of a key-structure of the endogenous pain inhibitory system, the pedunculopontine tegmental nucleus (PPTN), in post-ictal antinociceptive process through synaptic inactivation of the PPTN with cobalt chloride. Male Wistar rats (n = 6 or 7 per group), weighing 250-280 g, had the tail-flick baseline recorded and were submitted to a stereotaxic surgery for the introduction of a guide-cannula aiming at the PPTN. After 5 days of postoperative recovery, cobalt chloride (1 mM/0.2 µL) or physiological saline (0.2 µL) were microinjected into the PPTN and after 5 min, the tail-withdrawal latency was measured again at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 min after seizures evoked by intraperitoneal injection of pentylenetetrazole (64 mg/kg). The synaptic inactivation of PPTN decreased the post-ictal antinociceptive phenomenon, suggesting the involvement of PPTN intrinsic connections in the modulation of pain, during tonic-clonic seizures. These results showed that the PPTN may be crucially involved in the neural network that organizes the post-ictal analgesia.
['Mazzei-Silva|Elaine Cristina|EC|', 'de Oliveira|Rithiele Cristina|RC|', 'dos Anjos Garcia|Tayllon|T|', 'Falconi-Sobrinho|Luiz Luciano|LL|', 'Almada|Rafael Carvalho|RC|', 'Coimbra|Norberto Cysne|NC|']
D000818:Animals D002408:Catheters, Indwelling D002491:Central Nervous System Agents D003035:Cobalt D008297:Male D059225:Nociception D010147:Pain Measurement D058748:Pain Perception D017288:Pain Threshold D045042:Pedunculopontine Tegmental Nucleus D010433:Pentylenetetrazole D017208:Rats, Wistar D012154:Reticular Formation D012640:Seizures D013569:Synapses D013623:Tail D013997:Time Factors
pedunculopontine tegmental nucleus post-ictal antinociception tonic-clonic seizures synaptic transitory blockade