Pharmacological Interventions at the Spinal Cord: Intrathecal Injections

Both sensory inputs and motor outputs of the brain occur via the spinal cord. Spinalization, via a simple surgical cut, has allowed the elucidation of some of the intrinsic spinal circuitry underlying spinal reflexes. To understand the modulation of spinal processing by local spinal innervations and descending fibers from supraspinal structures to the spinal cord, a pharmacological approach is often more useful than a surgical one. The development of intrathecal injections (1 ) has permitted the introduction of specific agonists or antagonists locally into the spinal cord. In particular, the spinal action of opioids was thus proven (2 ).