Cardiovascular and arousal responses to single-lumen endotracheal and double-lumen endobronchial intubation in the normotensive and hypertensive elderly / 대한마취과학회지

BACKGROUND: Endotracheal intubation usually causes transient hypertension and tachycardia. The cardiovascular and arousal responses to endotracheal and endobronchial intubation were determined during rapid-sequence induction of anesthesia in normotensive and hypertensive elderly patients. METHODS: Patients requiring endotracheal intubation with (HT, n = 30) or without hypertension (NT, n = 30) and those requiring endobronchial intubation with (HB, n = 30) or without hypertension (NB, n = 30) were included in the study. Anesthesia was induced with intravenous thiopental 5 mg/kg followed by succinylcholine 1.5 mg/kg. After intubation, all subjects received 2% sevoflurane in 50% nitrous oxide and oxygen. Mean arterial pressure (MAP), heart rate (HR), plasma catecholamine concentration, and Bispectral Index (BIS) values, were measured before and after intubation. RESULTS: The intubation significantly increased MAP, HR, BIS values and plasma catecholamine concentrations in all groups, the peak value of increases was comparable between endotracheal and endobronchial intubation. However, pressor response persisted longer in the HB group than in the HT group (5.1 +/- 1.6 vs. 3.2 +/- 0.9 min, P < 0.05). The magnitude of increases in MAP and norepinephrine from pre-intubation values was greater in the hypertensive than in the normotensive group (P < 0.05), while there were no differences in those of HR and BIS between the hypertensive and normotensive groups. CONCLUSIONS: Cardiovascular response and arousal response, as measured by BIS, were similar in endobronchial and endotracheal intubation groups regardless of the presence or absence of hypertension except for prolonged pressor response in the HB group. However, the hypertensive patients showed enhanced cardiovascular responses than the normotensive patients.

The role of group III metabotropic receptors on opioid tolerance

BACKGROUND: Prolonged exposure to morphine causes tolerance to morphine-induced antinociception, yet the mechanisms of such tolerance are not fully understood. Although group I and II metabolic glutamate receptors (mGluRs) are involved in the modulation of morphine tolerance, the role of the group III mGluRs has not been determined. Therefore, we examined the effect of a group III mGluRs agonist on the morphine tolerance in the spinal cord. METHODS: An intrathecal infusion of morphine (40 nmol/microl/h) for 5 days was done to examine the development of morphine tolerance in male Sprague-Dawley rats. Noxious radiant heat was applied to the hindpaw and we measured the thermal withdrawal latency. To clarify the role of the group III mGluRs, an intrathecal group III mGluRs agonist (ACPT-III) or saline was administered to the morphine tolerant rats and we observed the change of the thermal withdrawal latency at 15, 30, 60, 90 and 120 min after delivery of ACPT-III. RESULTS: A continuous intrathecal infusion of morphine significantly increased the thermal withdrawal latency, as compared with the saline infused rats on day 1, with a decline on day 3 and the increase of withdrawal latency totally disappeared on day 5 (tolerance). Intrathecal ACPT-III increased the thermal withdrawal latency in the morphine tolerance rats. CONCLUSIONS: These results suggest that the group III mGluRs may be involved in the suppression of tolerance to morphine-induced antinociception at the spinal level.

Effect of Intrathecal Ginsenosides on Mechanical Allodynia in a Neuropathic Rat Model

BACKGROUND: Traditionally, ginseng has been widely used to manage various types of diseases. In particular, the analgesic effect of ginsenosides has been reported for inflammatory pain. However, the effect of ginsenosides on neuropathic pain has not been determined. The aim of this study was to examine the effect of ginsenosides on neuropathic pain in the spinal cord. METHODS: Neuropathic pain was induced by ligation of the lumbar 5, 6 spinal nerves in male Sprague-Dawley rats. Intrathecal catheters were placed into the subarachnoid space of rats that presented with mechanical allodynia. Mechanical allodynia was evaluated by measuring the withdrawal threshold to a von Frey filament applied to the plantar surface of rats. The analgesic effect of intrathecal ginsenosides was observed at 15, 30, 60, 90, 120, 150 and 180 min after delivery of the ginsenosides. RESULTS: After nerve ligation, the paw withdrawal threshold was significantly decreased at the ligated site. At the doses used in this study, intrathecal ginsenosides did not alter the withdrawal threshold in the ligated paw during the entire observation period. However, a dose of intrathecal ginsenosides greater than 1,500microg caused motor impairment. CONCLUSIONS: These results suggest that ginsenosides may not have a direct modulatory role in the transmission of neuropathic pain at the spinal level.

Antinociceptive Effects of Intrathecal Metabotropic Glutamate Receptor Compounds and Morphine in Rats / 대한통증학회지

BACKGROUND: Spinal metabotropic glutamate receptors (mGluRs) and opioid receptors are involved in the modulation of nociception. Although opioid receptors agonists are active for pain, the effects of the compounds for the mGluRs have not been definitely investigated at the spinal level. We examined the effects of the intrathecal mGluR compounds and morphine in the nociceptive test, and then we further clarified the role of the spinal mGluRs. In addition, the nature of the pharmacological interaction after the coadministration of mGluRs compounds with morphine was determined. METHODS: Catheters were inserted into the intrathecal space of male SD rats. For the induction of pain, 50microl of 5% formalin solution or a thermal stimulus was applied to the hindpaw. An isobolographic analysis was used for the evaluation of the drug interaction. RESULTS: Neither group I mGluR compounds nor group III mGluR compounds produced any antinociceptive effect in the formalin test. The group II mGluR agonist (APDC) had little effect on the formalin-induced nociception. The group II mGluR antagonist (LY 341495) caused a dose-dependent suppression of the phase 2 flinching response on the formalin test, but it did not reduce the phase 1 response of the formalin test nor did it increase the withdrawal latency of the thermal stimulus. Isobolographic analysis revealed a synergistic interaction after the intrathecal delivery of a LY 341495-morphine mixture. CONCLUSIONS: These results suggest that group II mGluRs are involved in the facilitated processing at the spinal level, and the combination of LY 341495 with morphine may be useful to manage the facilitated pain state.

Cardiovascular Responses to Endotracheal Intubation in Patients with Acute and Chronic Spinal Cord Injuries / 대한마취과학회지

BACKGROUND: We investigated whether the cardiovascular responses to intubation change as a function of the time elapsed in patients with spinal cord injury. METHODS: One hundred and fifty eight patients with traumatic complete spinal cord injury were grouped according to the time elapsed after injury (less than and more than 4 wks) and the level of injury (above C7, T1-T4, and below T5). There were six groups: acute quadriplegia (n = 28), chronic quadriplegia (n = 29), acute high paraplegia (n = 8), chronic high paraplegia (n = 11), acute low paraplegia (n = 29) and chronic low paraplegia (n = 53). Twenty-five patients with no spinal cord injury served as controls. Systolic arterial blood pressure (SAP), heart rate, and plasma concentrations of catecholamines were measured. RESULTS: The intubation did not affect SAP in acute and chronic quadriplegics, but significantly increased SAP in the other groups. The magnitude of peak increase was less in acute high paraplegics (P<0.05), but comparable in chronic high paraplegics, and acute and chronic low paraplegics to that of the controls. Heart rates were significantly increased in all groups. However, the magnitude of this increase was smaller in acute quadriplegics and in acute high paraplegics than in the controls (P<0.05). Plasma concentrations of norepinephrine increased in all groups except in acute quadriplegics (P<0.05). The magnitude of this increase was attenuated in chronic quadriplegics, accentuated in acute low paraplegics, and similar in acute and chronic high paraplegics and in chronic low paraplegics versus the controls. CONCLUSIONS: The cardiovascular and plasma catecholamine responses to endotracheal intubation may differ according to the time elapsed and the affected level in patients with complete spinal cord injuries.