title: Pentobarbital augments serotonin-mediated inhibition of cerebellar Purkinje cells.
abstract: The ability of pentobarbital to modify the direct effects of iontophoretically ejected serotonin on the firing rates of cerebellar Purkinje cells was examined. Serotonin elicited inhibition, excitation, or a biphasic effect on cerebellar Purkinje cells. With continuous application of iontophoretic pentobarbital at currents found to potentiate GABA-induced inhibition, serotonin-mediated inhibitions were also augmented consistently. When application of serotonin elicited excitation, including a late component of biphasic responses, iontophoretic pentobarbital converted the effect to, primarily, inhibition. Besides increasing the magnitude of serotonin-mediated inhibition, iontophoretic pentobarbital increased the duration of this effect. In another series of experiments using pentobarbital rather than urethan as the anesthetic, serotonin-mediated inhibition was significantly augmented for all ejection currents tested. The GABA antagonists bicuculline, pentylenetetrazole and picrotoxin attenuated pentobarbital augmentation of serotonin-elicited inhibition. We conclude that serotonin-mediated inhibition of Purkinje cells is modifiable by pentobarbital and this effect bears a strong semblance to the actions of barbiturates on GABAergic neurotransmission.
authors.affiliation: Department of Physiology, Texas Tech University Health Sciences Center, School of Medicine, Lubbock 79430.
authors.forename: J C
authors.initials: JC
authors.lastname: Strahlendorf
authors.forename: M
authors.initials: M
authors.lastname: Lee
authors.forename: J G
authors.initials: JG
authors.lastname: Netzeband
authors.forename: H K
authors.initials: HK
authors.lastname: Strahlendorf
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects*; D010424:Pentobarbital / Q000494:pharmacology*; D010433:Pentylenetetrazole / Q000494:pharmacology; D010852:Picrotoxin / Q000494:pharmacology; D011689:Purkinje Cells / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology* / Q000502:physiology
chemical_list: D010424:Pentobarbital; D010433:Pentylenetetrazole; D010852:Picrotoxin; D012701:Serotonin; D005680:gamma-Aminobutyric Acid