Cell subpopulations of nicotine-sensitive subfornical organ neurons in rat

• Published in: Neuroscience letters Vol. 442; no. 1; pp. 74 - 76
• Main Authors: Ono, Kentaro, Miyahara, Nobutaka, Inenaga, Kiyotoshi
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 05.09.2008; Elsevier
• Subjects: Angiotensin II - pharmacology; Animals; Biological and medical sciences; Cells, Cultured; Cerebral circulation. Blood-brain barrier. Choroid plexus. Cerebrospinal fluid. Circumventricular organ. Meninges; Fundamental and applied biological sciences. Psychology; Male; Membrane Potentials - drug effects; Membrane Potentials - physiology; Neurons - cytology; Neurons - drug effects; Neurons - metabolism; Nicotine; Nicotine - pharmacology; Nicotinic Agonists - pharmacology; Patch-Clamp Techniques; Rats; Rats, Wistar; Subfornical organ; Subfornical Organ - cytology; Subfornical Organ - drug effects; Subfornical Organ - metabolism; Vasoconstrictor Agents - pharmacology; Vertebrates: nervous system and sense organs; Whole-cell recording; Whole-cell recording; Subfornical organ; Nicotine; Ependymal organ; Vertebrata; Mammalia; Neuron; Rat; Animal; Rodentia; Central nervous system; Nicotine,Subfornical organ,Whole-cell recording; Encephalon
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2008.06.078

The subfornical organ (SFO), which is related to drinking and cardiovascular regulation, is activated by central application of nicotine (NIC) and angiotensin II (ANG). However, NIC-induced drinking is much smaller than ANG-induced one although approximately 60% of SFO neurons are affected by both NIC and ANG. Therefore, some specific subpopulations of SFO neurons for NIC or ANG may be related to such different drinking responses. To clarify subpopulations of NIC-sensitive neurons, electrophysiological properties of SFO neurons with the application of NIC was investigated at whole-cell patch-clamp recordings. Based on our developed electrophysiological criteria of the recovery kinetics of tetraethylammonium-resistant transient outward K + currents, two sub-types (F- and S-type neurons) were distinguished. Twenty-nine dissociated SFO neurons were examined to determine whether they showed NIC-induced inward currents. Most F-type neurons ( n = 19/21) showed NIC sensitivity, but most S-type neurons ( n = 7/8) did not. Our previous study had demonstrated that half of the F-type and all of the S-type units showed ANG sensitivity. These suggests that almost all of the NIC-sensitive SFO neurons were electrophysiologically classified as the F-type, but not S-type, and this differs in part from angiotensin sensitivity. The different subpopulations for chemical sensitivities in the SFO may be related to different drinking responses.