ABSTRACT

This chapter addresses some of the issues surrounding the contribution of surgery and anesthesia to the processing of spinal sensory inputs and of motor and sympathetic outputs. L. M. Kitahata’s group in Seattle in the 1960s was instrumental in showing that various anesthetics could affect different classes of spinal dorsal horn neuron at concentrations relevant to a surgical plane of anesthesia. Subsequent work has elaborated the actions and has confirmed that anesthetics do alter sensory processing at the spinal cord level. Different groups of animals were investigated with either different anesthetics or different degrees of surgery to the spinal column and cord. Counts of actions potentials elicited during phases of each stimulus were logged onto computer and were analyzed on line in terms of percentage changes from the mean of the last three pre-test control cycles. Mature sheep were implanted in an initial surgical operation under halothane anesthesia.