title: Raphe-septal neurons changes in sensitivity to desipramine following an early septal lesion in the rat.
abstract: 1. The electrophysiological responsivity to desipramine (DMI) applied by systemic or local route was tested in Wistar female rats submitted to a wide lesion in the lateral septal area on the 8th day after birth. 2. One year after a septal lesion, the dorsal raphe nucleus (DRN) stimulation produced an initial brief response in lateral septal and CA1/CA3 neurons. In the control and sham-lesion groups, most recordings showed only this initial brief response (non-late responding neurons); however, in the lesion group most of the recorded neurons showed an afterdischarge. 3. DMI (2.14 mg/kg, 21 days, i.p.) increased the firing rate in septal and CA1/CA3 non-late responding neurons. In the equivalent septal neurons from lesion group, DMI produced the inverse effect, i.e., a decreased firing rate. 4. In septal non-late responding neurons, DMI (2 mM; 10-15 nAmps, 0.5 sec) applied by microiontophoresis increased the firing rate only after long-term systemic DMI impregnation. The response to locally applied DMI did not occur in the lesion group even after long-term DMI treatment. 5. In conclusion, an early lateral septal lesion canceled the response of intermediate-dorsal septal neurons to DMI applied by systemic and local routes.
authors.affiliation: Departamento de Fisiología, Institudo de Investigaciones, Biomédicas, UNAM, México.
authors.forename: M
authors.initials: M
authors.lastname: Molina
authors.forename: J L
authors.initials: JL
authors.lastname: Díaz-Meza
authors.forename: M
authors.initials: M
authors.lastname: Saavedra
authors.forename: M
authors.initials: M
authors.lastname: Ortiz
authors.forename: C M
authors.initials: CM
authors.lastname: Contreras
mesh_terms: D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D001930:Brain Injuries / Q000503:physiopathology*; D003891:Desipramine / Q000494:pharmacology*; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D007478:Iontophoresis; D008564:Membrane Potentials / Q000502:physiology; D009474:Neurons / Q000187:drug effects*; D011903:Raphe Nuclei / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000929:Antidepressive Agents, Tricyclic; D003891:Desipramine