Comparison of analgesic techniques for antler removal in wapiti. (1/5)

The purpose of this research was to compare the effectiveness of ring block anesthesia (LA) and electroanesthesia (A) for antler removal in elk given a long-acting tranquilizer to remove stress from restraint. Thirty-two male wapiti were given 1 mg/kg body weight of zuclopenthixol acetate; the next day, they were restrained in a hydraulic chute, provided with electroanesthesia or a lidocaine ring block, and had their antlers removed. Behavioral response to antler removal was scored. Significantly more (P = 0.032) animals responded to antler removal in the EA group. Heart rates and arterial pressures were measured by a catheter connected to a physiological monitor. Heart rate increased significantly over time with EA, but not with LA. Heart rate increased from baseline significantly more in the EA group immediately prior to antler removal (P = 0.017), immediately post antler removal (P = 0.001), and at 1 min post antler removal (P = 0.037). It was concluded that EA is not as effective a method of anesthesia as is LA for antler removal.  (+info)

The penetration of some cations into muscle. (2/5)

The influx of Na(+), K(+), Rb(+), and Cs(+) into frog sartorius muscle has been followed. The results show that a maximum rate is found for K(+), while Na(+) and Cs(+) penetrate much more slowly. Similar measurements with Ca(++), Ba(++), and Ra(++) show that Ba(++) penetrates at a rate somewhat greater than that of either Ca(++) or Ra(++). All these divalent cations, however, penetrate at rates much slower than do the alkali cations. The results obtained are discussed with reference to a model that has been developed to explain the different penetration rates for the alkali cations.  (+info)

The noxious effects of electroimmobilization in adult Holstein cows: a pilot study. (3/5)

Ten adult Holstein cows were used in an experiment to determine whether the induction of electroimmobilization was a noxious event. The cows were halter trained and accustomed to being led into a set of stocks. The time taken for the cattle to walk the last ten metres into the stocks was recorded. The heart rate of the cow was recorded for a three minute period prior to a ten second exposure to a high pitched sound (the conditioning stimulus). Measurements were collected for three repetitions and then the cows were assigned to two groups of five. One group was immobilized for 30 seconds using a commercial electroimmobilizer, the other group was not treated. This procedure was repeated ten times over a period of eight days. The cows were then exposed to the conditioning stimulus and their response observed. The treated group took significantly (P less than 0.05) longer to get into the stocks and the regression slopes for heart rate were significantly different from the control group. The treated cows responded to the conditioning stimulus at five and nine months after the end of the conditioning period. Adult Holstein cows regarded electroimmobilization as a noxious event and were very strongly conditioned to this stimulus.  (+info)

Reduced anesthetic requirement after electrical stimulation of periaqueductal gray matter. (4/5)

To determine whether electrical stimulation of the periaqueductal gray region decreases anesthetic requirement, the authors studied the effect of such stimulation on the MAC of halothane and 60% nitrous oxide in 33 patients. These patients, who were undergoing implantation of a radio-frequency-coupled receiver and connection of that receiver to electrodes previously implanted in the periaqueductal gray area, were assigned randomly to receive (n = 16) or not receive (n = 17) electrical stimulation 1 h before surgery. The mean value (+/- SEM) for the minimum alveolar concentration of halothane combined with 60% nitrous oxide was significantly less (P less than 0.001) for patients who were stimulated preoperatively (0.15 +/- 0.05%) than for those who were not (0.51 +/- 0.02%). The authors conclude that stimulation of the periaqueductal gray region decreases anesthetic requirements and believe that at least three mechanisms are possible: a nonspecific narcotic-like effect, a specific effect on a pain pathway, or an effect on specific neural pathways that affect anesthetic requirements secondary to changes in regional concentrations of neurotransmitters.  (+info)

Electrical stimulation for the relief of pain. (5/5)

Electrical stimulation can relieve some severe and otherwise persisting pains. At its best it can be associated with either a gradual reduction in the pain or an increased ability by the patient to control his suffering. It seems particularly appropriate for use in the field of benign persistent pain. Equipment design and materials, particularly for implantable circuits, are not perfect. Movement towards percutaneous implantation, obviating the need for open operation, seems progressively more popular. Any unit or group using this form of treatment, must be prepared to provide major technical facilities, both in the form of people and equipment in order to cater for the many purely technical problems that occur. A great deal of knowledge both neurophysiological and neurochemical seems to be accruing from the clinical use of electrical stimulation. We would do well to take advantage of this opportunity, in the hope that it might lead us to a better understanding of the functioning of the nervous system. This consideration remarkably parallels an observation made by John Hunter in his presentation to the Royal Society in 1773 (13) which anticipated the realisation of the part played by electricity in the function of nerves. Following his description of the extraordinary innervation of the electric organs of the Torpedo fish, he wrote: 'How far this may be connected with the power of the nerves in general, or how far it may lead to an explanation of their operations, time and future discoveries alone can fully determine.'  (+info)