Intracardiac phenylbiguanide causes excitation of spinal neurons by activation of cardiac sympathetic afferents.
The responses of spinothalamic, spinoreticular, and unidentified spinal neurons to intracardiac administration of phenylbiguanide, a 5-HT3 receptor agonist, were examined in anesthetized cats and monkeys. Eighteen neurons were excited, 5 were inhibited, and 12 were unresponsive to this stimulus. Results suggest that cardiac sympathetic afferents mediate the excitatory responses produced by phenylbiguanide, because bilateral cervical vagotomy failed to block these responses, and aortic injections of phenylbiguanide had little effect on cell activity.
Blair
R W
RW
Department of Physiology and Biophysics, University of Oklahoma Health Sciences Center, Oklahoma City 73190.
Chandler
M J
MJ
Bolser
D C
DC
Foreman
R D
RD
D000320:Adrenergic Fibers / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001645:Biguanides / Q000008:administration & dosage / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D006321:Heart / Q000187:drug effects / Q000294:innervation*; D008252:Macaca fascicularis; D009434:Neural Pathways / Q000187:drug effects; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology; D011985:Receptors, Serotonin / Q000187:drug effects; D013127:Spinal Nerves / Q000187:drug effects* / Q000502:physiology; D014628:Vagotomy
D001645:Biguanides; D011985:Receptors, Serotonin; C008846:phenyl biguanide