Hyperesthesia: Increased sensitivity to cutaneous stimulation due to a diminished threshold or an increased response to stimuli.Diagnostic Techniques, Neurological: Methods and procedures for the diagnosis of diseases of the nervous system, central and peripheral, or demonstration of neurologic function or dysfunction.Sciatic Nerve: A nerve which originates in the lumbar and sacral spinal cord (L4 to S3) and supplies motor and sensory innervation to the lower extremity. The sciatic nerve, which is the main continuation of the sacral plexus, is the largest nerve in the body. It has two major branches, the TIBIAL NERVE and the PERONEAL NERVE.Suburban Population: The inhabitants of peripheral or adjacent areas of a city or town.Injections, Spinal: Introduction of therapeutic agents into the spinal region using a needle and syringe.Carrageenan: A water-soluble extractive mixture of sulfated polysaccharides from RED ALGAE. Chief sources are the Irish moss CHONDRUS CRISPUS (Carrageen), and Gigartina stellata. It is used as a stabilizer, for suspending COCOA in chocolate manufacture, and to clarify BEVERAGES.Dizocilpine Maleate: A potent noncompetitive antagonist of the NMDA receptor (RECEPTORS, N-METHYL-D-ASPARTATE) used mainly as a research tool. The drug has been considered for the wide variety of neurodegenerative conditions or disorders in which NMDA receptors may play an important role. Its use has been primarily limited to animal and tissue experiments because of its psychotropic effects.Idazoxan: A benzodioxane-linked imidazole that has alpha-2 adrenoceptor antagonist activity.Hot Temperature: Presence of warmth or heat or a temperature notably higher than an accustomed norm.Biphenyl CompoundsSensory Thresholds: The minimum amount of stimulus energy necessary to elicit a sensory response.Morphine: The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.