Clinical and experimental pharmacology & physiology
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Clin. Exp. Pharmacol. Physiol. · May 1998
Respiratory sinus dysrhythmia persists in transplanted human hearts following autonomic blockade.
1. The present study was performed to test whether beat-to-beat cardiovascular control in cardiac allograft recipients resides in cholinergic and/or adrenergic nerves that are intrinsic to the heart. 2. Heart rate (HR) fluctuations synchronous with respiration during spontaneous, double tidal volume and metronome-synchronized breathing were quantified in 13 human heart transplant recipients. ⋯ Thus, as the amplitude of pulse pressure increased, respiration accounted for a smaller percentage of HR variation. 4. In conclusion, RSA persists and the magnitude of CPS increases following combined autonomic blockade. These studies suggest that while RSA after cardiac transplantation is not cholinergically or adrenergically mediated, it may be related to mechanical stretch of the sinus node caused by changes in intrathoracic pressure and perfusion pressure.
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Clin. Exp. Pharmacol. Physiol. · Sep 1997
Psychomotor performance during initial stage of exposure to halothane, enflurane, isoflurane and sevoflurane in mice.
1. The dose-response relationship during the pre-anaesthetic and pre-equilibrium state of four inhalation anaesthetics (halothane, enflurane, isoflurane and sevoflurane) on fixed-ratio schedule-controlled behaviour was studied in mice. 2. ⋯ Sevoflurane did not increase schedule-controlled behavioural responses at any concentration. 4. The effect of subanaesthetic concentrations of inhalation anaesthetics on psychomotor performance can be evaluated as changes in the response rate in schedule-controlled behaviour.
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Clin. Exp. Pharmacol. Physiol. · May 1997
Concentration-effect relationships of morphine and morphine-6 beta-glucuronide in the rat.
1. The aims of the present study were to determine the relationship between the antinociceptive effect and concentrations of morphine and morphine-6 beta-glucuronide (M6G) in plasma and in the brain. 2. Morphine (14.0 and 28.0 mumol/kg) or M6G (8.67 and 17.3 mumol/kg) were administered s.c. to male Hooded-Wistar rats. ⋯ Concentrations of M6G in the brain were below the limit of quantification. The relationship between antinociceptive effect and plasma morphine or M6G were characterized by counter-clockwise hysteresis loops, probably reflecting a delay in crossing the blood-brain barrier. 4. Morphine-6 beta-glucuronide was approximately equipotent to morphine on the basis of dose, but substantially more potent on the basis of brain concentration.
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Clin. Exp. Pharmacol. Physiol. · Jan 1997
ReviewPharmacological action of Australian animal venoms.
1. Australia has some of the most venomous fauna in the world. Although humans are not usually perceived as being predators against these animals they are often envenomated, accidentally or otherwise. ⋯ Lampona cylindrata). Other venoms, such as those of the jumper ant (Myrmecia pilosula) and bull ant (M. pyriformis), may produce only mild skin irritation to the majority of humans but a severe anaphylactic response in sensitized victims. 4. While there has been a renewed interest in toxinology, further research is required to fully elucidate the pharmacological action of many of these venoms.
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Clin. Exp. Pharmacol. Physiol. · Oct 1996
ReviewClearing 'the fog on the Tyne': can the quality of therapeutics be assessed?
1. The rise in prescribing costs in developed countries is a concern for all physicians, but a particular challenge for clinical pharmacologists. 2. There are wide variations in the amounts and types of drugs prescribed in developed countries. 3. ⋯ A consensus process is described in which primary care physicians developed criteria of prescribing quality, using data readily available within the UK. Practitioners scores using these criteria did not correlate directly with prescribing costs, indicating that cost alone cannot be used as criterion of quality. 5. The measurement of quality in therapeutics remains an important challenge for the future.