5-Hydroxytryptamine modulates spike frequency regulation in reticulospinal neurons involved in the control of locomotion in lamprey.
To investigate the effects of 5-hydroxytryptamine (5-HT) on reticulospinal neurons involved in the initiation and control of locomotion in lamprey, 5-HT (10 mM) was locally pressure ejected on the dorsal surface of the brainstem during intracellular recordings from identified reticulospinal neurons in the in vitro brainstem-spinal cord preparation. 5-HT induced a reduction of the late afterhyperpolarization (AHP) following the spike due to a reduction of a Ca(2+)-activated K+ current. In addition, 5-HT caused a resting membrane hyperpolarization in a proportion of these cells. Due to the 5-HT induced reduction of the AHP, reticulospinal cells, including those that became hyperpolarized by an application of 5-HT, discharged at a higher rate after 5-HT as a response to the same excitatory drive.
Di Prisco
G V
GV
Nobel Institute for Neurophysiology, Karolinska Institutet, Stockholm, Sweden.
Dubuc
R
R
Wallén
P
P
Grillner
S
S
D000818:Animals; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D007798:Lampreys; D007814:Larva; D008564:Membrane Potentials / Q000187:drug effects; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D012154:Reticular Formation / Q000187:drug effects / Q000502:physiology*; D012249:Rhombencephalon / Q000187:drug effects / Q000502:physiology*; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D013757:Tetraethylammonium Compounds; D013779:Tetrodotoxin; D016202:N-Methylaspartate; D019789:Tetraethylammonium