Regional expression of the anesthetic-activated potassium channel TRESK in the rat nervous system.

The two-pore-domain potassium (K(2P)) channels contribute to background (leak) potassium currents maintaining the resting membrane potential to play an important role in regulating neuronal excitability. As such they may contribute to nociception and the mechanism of action of volatile anesthetics. In the present study, we examined the protein expression pattern of the K(2P) channel TRESK in the rat central nervous system (CNS) and peripheral nervous system (PNS) by immunohistochemistry. The regional distribution expression pattern of TRESK has both similarities and significant differences from that of other K(2P) channels expressed in the CNS. TRESK expression is broadly found in the brain, spinal cord and dorsal root ganglia (DRG). TRESK expression is highest in important CNS structures, such as specific cortical layers, periaqueductal gray (PAG), granule cell layer of the cerebellum, and dorsal horn of the spinal cord. TRESK expression is also high in small and medium sized DRG neurons. These results provide an anatomic basis for identifying functional roles of TRESK in the rat nervous system.

A comparison of cervical epidural analgesia and intravenous patient-controlled analgesia after mastectomy with immediate latissimus dorsi flap breast reconstruction.

BACKGROUND: Breast reconstruction following mastectomy has become increasingly popular in recent years. The purpose of this study was to compare the efficacy of cervical epidural patient-controlled analgesia (CEA) and intravenous patient-controlled analgesia (IV-PCA) for controlling the postoperative pain and the side effects after mastectomy with immediate Latissimus dorsi (LD) flap breast reconstruction. METHODS: Sixty patients who were to undergo mastectomy with immediate LD flap breast reconstruction were randomly assigned to receive CEA [Group CEA, (n = 30), 0.15% ropivacaine + fentanyl 4 microg/ml] or IV-PCA [Group IV-PCA (n = 30) fentanyl 20 microg/kg + ketorolac 3 mg/kg] for postoperative pain control via a PCA pump (basal rate: 2 ml/h, bolus: 2 ml, lock out interval: 15 min) after their operation. Before general anesthesia, an epidural catheter was inserted at the cervical (C)7-thoracic (T)1 level in the patients of the CEA group. The resting visual analogue scale (VAS) for pain, the systolic blood pressure, the heart rate and the side effects were recorded for 48 hours after operation. RESULTS: The VAS at rest was significantly lower in the CEA group than that in the IV-PCA group at 16 hours after surgery. The CEA group required less additional analgesics as compared with the group IV- PCA. There were no significant differences in the systolic blood pressure, the heart rate and the incidence of side effects between the two groups. CONCLUSIONS: We conclude that cervical epidural analgesia, as compared with intravenous patient-controlled analgesia, provides effective pain control and it shows a similar incidence of side effects after mastectomy with immediate LD flap breast reconstruction.