British journal of anaesthesia
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Nociceptin/orphanin FQ (N/OFQ) is the endogenous agonist of the orphan opioid receptor-like receptor (NOP receptor, previously termed ORL1), a novel member of the opioid receptor family. The aim of the present study, using in vitro newborn rat preparations, was to elucidate the roles N/OFQ and the NOP receptor play in medullary generation of respiratory rhythm. ⋯ N/OFQ acts as a neuromodulator to reduce fR in the respiratory rhythm- generating centre of the medulla oblongata, and this action of N/OFQ is mediated by NOP receptors.
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Thiopental sometimes causes bronchospasm during induction of anaesthesia. In addition, we have reported previously that thiopental produced transient bronchospasm, which was blocked by atropine pretreatment, and worsened histamine-induced bronchoconstriction in dogs. Previous in vitro reports suggest that synthesis of contractile cyclooxygenase products, such as thromboxane A(2), may be involved in the mechanism of bronchospasm. However, the in vivo spastic effects have not been defined comprehensively. ⋯ The present study indicates that thiopental may attenuate or worsen bronchoconstriction induced by muscarinic or serotonin receptor stimulation, respectively. The synthesis of contractile cyclooxygenase products and cholinergic stimulation may not be involved in the contractile effect of thiopental on serotonin bronchoconstriction.
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Direct or indirect acting cholinergic muscarinic agonists such as neostigmine, are potent antinociceptives when administered intrathecally (i.t.). This study examines whether spinal neostigmine tolerance and cross-tolerance to spinal morphine occurs. ⋯ Thus, unidirectional cross-tolerance from morphine to neostigmine was evident. Previous studies suggest morphine has a cholinergic mechanism of action partially accounting for its antinociceptive effect, which may explain this observed unidirectional cross-tolerance.
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Comment Letter Multicenter Study
Effectiveness of acute postoperative pain management.