Evidence for the presence of nicotinic receptors on rat subfornical organ neurons.
The sensitivity of subfornical organ (SFO) neurons in rat slice preparations to nicotine was studied using whole-cell patch-clamp recordings and immunohistochemistry. In the current-clamp mode, nicotine at 10 microM depolarized the membrane and increased the firing rate. In the voltage-clamp mode, nicotine elicited inward currents in a dose-dependent manner. The net current-voltage relationships of the nicotine-induced currents displayed inward rectification above -40 mV. The relatively alpha4beta2-selective nicotinic acetylcholine (ACh) receptor antagonist, dihydro-beta-erythroidine, reduced the peak amplitudes of the nicotine-induced inward currents. Immunohistochemical experiments with alpha4 antibody showed the existence of immunopositive cells in the subfornical organ. These results suggest that neurons in the subfornical organ are excited via alpha4beta2 nicotinic acetylcholine receptors.
Ono
Kentaro
K
Department of Physiology, Kyushu Dental College, 2-6-1 Manazuru, Kokurakitaku, Kitakyushu 803-8580, Japan.
Honda
Eiko
E
Toyono
Takashi
T
Kataoka
Shinji
S
Nakamura
Taiji
T
Inenaga
Kiyotoshi
K
D000818:Animals; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000737:chemistry / Q000187:drug effects / Q000502:physiology; D018722:Nicotinic Agonists / Q000494:pharmacology; D018733:Nicotinic Antagonists / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011978:Receptors, Nicotinic / Q000032:analysis / Q000502:physiology*; D013356:Subfornical Organ / Q000737:chemistry / Q000187:drug effects / Q000502:physiology*
D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic