Is neurotransmitter release involved in the mechanism of general anesthesia?

Introduction: It is believed that neurotransmitters release modulates general anesthesia via several receptors system which are molecular targets for anesthetic agents in young-adult rats. However, middle-aged rats have rarely been used. Therefore, we studied in this age group.

Ketamine and propofol have opposite effects on postanesthetic sleep architecture in rats: relevance to the endogenous sleep-wakefulness substances orexin and melanin-concentrating hormone.

Background: Anesthesia and surgery disturb sleep. Disturbed sleep adversely affects postoperative complications involving the cardiovascular system, diabetes, and infection. General anesthetics share neuronal mechanisms involving endogenous sleep-wakefulness-related substances, such as orexin (OX) and melanin-concentrating hormone (MCH).

[Analgesic efficacy and clinical safety of intraperitoneal instillation combined with rectus sheath block using ropivacaine for pain relief after laparoscopic gynecological surgery].

Background: The aim of this study was to evaluate the analgesic efficacy and safety of rectus sheath block combined with intraperitoneal instillation using two doses of ropivacaine in patients undergoing laparoscopic gynecological surgery.

Methods: Altogether 53 consenting women were randomized to receive intraperitoneal infiltration with 0.25% ropivacaine or 0.

Quantitative measurement of blood remifentanil concentration: development of a new method and clinical application.

We have developed a new detection method of blood remifentanil concentration using a gas chromatography-mass spectrometry(GC-MS) with fentanyl as the internal standard(IS). The detection was performed at m/z 168 and 245 for remifentanil and fentanyl, respectively. In addition, the retention times of remifentanil and fentanyl were 5 min 45 s and 6 min 51 s, respectively.

Brief reports: plasma ropivacaine concentrations after ultrasound-guided rectus sheath block in patients undergoing lower abdominal surgery.

A rectus sheath block can provide postoperative analgesia for midline incisions. However, information regarding the pharmacokinetics of local anesthetics used in this block is lacking. In this study, we detail the time course of ropivacaine concentrations after this block.

Antinociceptive effects of neurotropin in a rat model of central neuropathic pain: DSP-4 induced noradrenergic lesion.

Neurotropin is a nonprotein extract isolated from inflamed skin of rabbits inoculated with vaccinia virus, and used for treatment of neuropathic pain. In the present study, we have determined whether neurotropin could exert antinociceptive action using the central neuropathic pain model that we recently established. Rats were randomly allocated to 3 groups: Sham group (n=20), DSP-4 [N-(-2-chloroethyl)-N-ethyl-2-bromobenzylamine] group (50mg/kg ip, n=18), and DSP-4+5,7-DHT [5,7-dihydroxytryptamine] group (ip DSP-4 50mg/kg+icv 5,7-DHT 200μg, n=18).

A marked increase in gastric fluid volume during cardiopulmonary bypass.

Major physiological stress occurs during cardiac surgery with cardiopulmonary bypass. This is related to hypothermia and artificial organ perfusion. Thus, serious gastrointestinal complications, particularly upper gastrointestinal bleeding, sometimes follow cardiac surgery.

The effects of neuropeptide S on general anesthesia in rats.

Background: Neuropeptide S (NPS) and its receptor (NPSR) is a novel neuropeptide system that regulates arousal and anxiety. A link between natural sleep and general anesthesia has been suggested. Therefore, we hypothesized that the NPS neuronal system may also modulate general anesthesia.

Leg massage therapy promotes psychological relaxation and reinforces the first-line host defense in cancer patients.

Purpose: Patients with cancer suffer a wide range of physical symptoms coupled with psychological stress. Moreover, cancer chemotherapy induces immunosuppression and consequently causes respiratory infections. Massage therapy has been reported to reduce symptoms in cancer patients via an increase in psychosocial relaxation and to enhance and/or improve immune function.

Back massage therapy promotes psychological relaxation and an increase in salivary chromogranin A release.

Massage therapy promotes psychosocial relaxation, reduces stress and has been reported to improve the immune function. As such, massage therapy is currently used in palliative care for the relief of anxiety and pain. Although psychosocial status has been evaluated using subjective psychological tests, such as State-Trait Anxiety Inventory (STAI), subjective psychological tests are of limited value if the subjects fail to report reliably.

Plasma orexin A increases at emergence from sevoflurane-fentanyl anesthesia in patients undergoing ophthalmologic surgery.

Central orexinergic and noradrenergic neurons are involved in the control of sleep and wakefulness. In addition, previous reports suggest that both neurons may have an important role to play in general anesthesia. In the present study, we have determined whether general anesthesia would affect plasma orexin A (OXA) and norepinephrine concentrations.

A central neuropathic pain model by DSP-4 induced lesion of noradrenergic neurons: preliminary report.

Neuropathic pain models are classified as central and peripheral pain models. Although various peripheral neuropathic pain models are established, central pain models are based only on spinal cord injury. DSP-4 is a competitive inhibitor of norepinephrine uptake that selectively degenerates the locus coeruleus (LC)-noradrenergic neurons projection to the cerebral cortex and hippocampus.

Nitrous oxide and xenon increase noradrenaline release in the cerebral cortex in vivo and in vitro.

Noradrenaline in the central nervous system plays an important role in regulating physiological functions, and is a key mechanistic component of general anesthesia. The purpose of this present study was to determine if nitrous oxide and xenon modulate noradrenaline release in the cerebral cortex. We performed a series of in vivo and in vitro experiments in rats.

Efficacy of a single 24-hour pre-anesthetic dose of proton pump inhibitors.

Background And Aim: The H(2) receptor antagonist roxatidine is routinely used as an oral pre-anesthetic medication in surgical patients at night and 2 h before surgery. In the present study, we have compared the effects of roxatidine, rabeprazole and lansoprazole given singly at night as an alternative to the standard double roxatidine medication.

Methods: 120 adult patients undergoing urological surgery were randomly assigned to three groups: roxatidine, rabeprazole and lansoprazole (n = 40 each).

The effects of benzodiazepines on urotensin II-stimulated norepinephrine release from rat cerebrocortical slices.

Background: Urotensin II (UII) and its receptor (UT) are implicated in mood disorders, such as stress and anxiety, and this may result, at least in part, from increased norepinephrine release from the cerebral cortex. Benzodiazepines have been widely used as hypnotics and anxiolytics, producing a decrease in cerebrocortical norepinephrine release. We hypothesized that there was some interaction between benzodiazepines and the UII system in the cerebral cortex.

Orexin A decreases ketamine-induced anesthesia time in the rat: the relevance to brain noradrenergic neuronal activity.

Background: Orexins (OXs) regulate wakefulness, and a lack of OX Type-I receptors cause narcolepsy. OX selectively increases norepinephrine (NE) release from rat cerebral cortical slices, and brain noradrenergic neurons are involved in the sleep-wakefulness cycle. Ketamine increases NE release from the rat cerebral cortex.

Interaction between orexinergic neurons and NMDA receptors in the control of locus coeruleus-cerebrocortical noradrenergic activity of the rat.

Several studies suggest that NMDA glutamate receptors may play an important role in the activation of a number of brain regions by orexin (OX). We hypothesized that OX and NMDA receptors may interact with cerebrocortical noradrenergic neuron originating from the locus coeruleus (LC). To test this hypothesis, using rats as experimental animals, we examined (i) in vitro effects of MK801 on OXA-evoked norepinephrine release from rat cerebrocortical slices, (ii) in vivo interaction between OXA and the NMDA receptor antagonist, MK801 on norepinephrine release from the prefrontal cortex assessed using microdialysis and (iii) MK801 and OXA-modulation of the electroencephalogram (EEG).

Urotensin II evokes neurotransmitter release from rat cerebrocortical slices.

Urotensin II (UII) has been reported to modulate rapid eye movement (REM) sleep via activation of brainstem cholinergic neurons and REM sleep is regulated by locus coerleus (LC)-cerebrocortical noradrenergic neurons. We hypothesized that UII may activate LC-cerebrocortical noradrenergic neurons. To test this hypothesis, we have examined the effects of UII on norepinephrine release from rat cerebrocortical slices.

Role of the orexinergic system in acute haemorrhage in the rat.

Orexins (OXs) stimulate sympathetic nerve activity to increase arterial pressure (AP) and heart rate (HR). We have previously reported that the OX(1)-receptor antagonist SB-334867 reversed the sympathomimetic actions of orexin A (OXA). In the present study we have investigated the role(s) of the orexinergic system in sympathetic activation during haemorrhage in rats.

Does long-term medication with a proton pump inhibitor induce a tolerance to H2 receptor antagonist?

Background: Previous reports suggest that complete tolerance to H2 receptor antagonists (H2RAs) in patients with regular H2RA medication may be due to hypergastrinemia-increased histamine synthesis or upregulation of H2 receptors. As proton pump inhibitors (PPIs) have been reported to induce hypergastrinemia (similar to H2RAs), patients receiving long-term medication with PPIs may show tolerance to preanesthetic H2RA. Therefore, we studied the efficacy of an H2RA, roxatidine, in patients receiving long-term PPI medication.

The effects of benzodiazepines on orexinergic systems in rat cerebrocortical slices.

Background: As orexinergic (OXergic) neurons have been reported to mediate emotional changes, benzodiazepines might interact with OXergic neurons.

Methods: We examined the interactions between OXergic neurons and benzodiazepine receptors in orexin-A (100 nM) and K+ (25 mM)-evoked norepinephrine release from rat cerebrocortical slices.

Results: Midazolam, diazepam, and flunitrazepam concentration-dependently inhibited both OX-A- and K+-evoked norepinephrine release.

The relationship between salivary biomarkers and state-trait anxiety inventory score under mental arithmetic stress: a pilot study.

Measurement of stress hormones is a common objective method for assessment of mental stress. However, the stress of blood sampling alone may also increase stress hormone levels. In the present study, we sampled salivary biomarkers from healthy volunteers under noninvasive conditions and determined their efficacy to assess mental stress.

The efficacy of preanesthetic proton pump inhibitor treatment for patients on long-term H2 antagonist therapy.

Unlabelled: We previously reported that H2-antagonist medication given for longer than 4 wk may produce complete tolerance to preanesthetic H2 antagonist therapy. In this study, we evaluated the efficacy of preanesthetic proton pump inhibitor (PPI; oral rabeprazol) use in patients receiving regular H2-antagonist (oral famotidine) therapy for more than 4 wk. Forty-eight patients with assumed complete tolerance to H2 antagonists undergoing elective surgery were recruited and randomly assigned to receive either a preanesthetic PPI (rabeprazol 20 mg; n = 24) or H2-antagonist (H2 group; roxatidine 75 mg; n = 24) at 9:00 pm on the day before surgery and 2 h before the induction of anesthesia.

Lack of interaction between orexinergic and alpha2-adrenergic neuronal systems in rat cerebrocortical slices.

Orexinergic and norepinephrinergic alpha2-adrenoceptor expressing neurons contribute to the regulation of the sleep-wakefulness cycle. In the present study, we have examined a possible interaction between orexinergic and alpha2-adrenergic systems in orexin-A (100 nM)- and K+ (25 mM)-evoked norepinephrine release from slices of rat cerebrocortex. In this tissue norepinephrinergic neurons are predominantly innervated via the locus coeruleus.

Regular use of H2 blockers reduces the efficacy of roxatidine to control gastric pH and volume.

Purpose: H(2) antagonist premedication is common in surgical patients to control gastric pH and volume. However, several reports suggest that long-term medication may produce tolerance. Therefore, we studied the efficacy of a preanesthetic H(2) antagonist (oral roxatidine) in patients on regular H(2) antagonist therapy.