Characteristics of blood pressure and nictitating membrane reflexes elicited by electric stimulation of sciatic nerve in conscious and in anaesthetized cats.

Blood pressure (BP) reflexes and contractions of the nicitating membrane (NM) elicited by sustained (60 sec) stimulation of the sciatic nerve have been simultaneously recorded in gallamine immobilized conscious cats and following the administration of chloralose-urethane (50 and 300 mg/kg, respectively). By varying the stimulation parameters in a wide range, voltage and frequency characteristics of BP and NM reflexes have been plotted. In order to reduce the great number of possible BP-characteristics, the "dose" of stimulation (the product of voltage, impulse duration, frequency and of the stimulation period) has been introduced to plot "dose"-response curves. Differences in the BP and NM responses, and between awake and anaesthetized states as well as their probable causes are discussed. On the basis of the characteristic curves, a complex consisting of two facilitatory and at least one inhibitory mechanism has been supposed to be involved in the CNS integration of somato-sympathetic reflexes.