Electrophysiological and neurochemical characterization of neurons of the medial preoptic area in Japanese quail ( Coturnix japonica)

• Published in: Brain research 2004-12, Vol.1029 (2), p.224-240
• Main Authors: Cornil, Charlotte A., Seutin, Vincent, Motte, Patrick, Balthazart, Jacques
• Format: Article
• Language: English
• Subjects: 6-Cyano-7-nitroquinoxaline-2,3-dione - pharmacology; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid - pharmacology; Animals; Aromatase; Aromatase - metabolism; Biological and medical sciences; Central nervous system; Coturnix - physiology; Coturnix japonica; Dopamine; Dopamine - pharmacology; Electrophysiology; Excitatory Amino Acid Agonists - pharmacology; Excitatory Amino Acid Antagonists - pharmacology; Excitatory Postsynaptic Potentials - drug effects; Excitatory Postsynaptic Potentials - physiology; Fundamental and applied biological sciences. Psychology; GABA Agonists - pharmacology; GABA Antagonists - pharmacology; Glutamate; Intracellular recording; Isonicotinic Acids - pharmacology; Kainic Acid - pharmacology; Male; N-Methylaspartate - pharmacology; Neurons - physiology; Norepinephrine; Norepinephrine - pharmacology; Preoptic Area - cytology; Preoptic Area - physiology; Pyridazines - pharmacology; Sexual behavior; Sympathomimetics - pharmacology; Vertebrates: nervous system and sense organs
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2004.09.047

Intracellular recordings of medial preoptic neurons demonstrated that most neurons show a spontaneous firing, a linear I– V relationship and low-threshold-like events suppressed by the application of Ni 2+. Some neurons had a depolarizing sag of the membrane potential in response to hyperpolarizing current pulses. The majority of the cells exhibited a robust spontaneous synaptic activity suppressed by SR95531 (100 μM), a GABA A receptor antagonist, and/or by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 10 μM), an ( RS)-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate (KA) glutamate receptor antagonist. Most neurons were affected by the application of AMPA (10 μM), kainate (30 μM), N-methyl- d-aspartic acid (NMDA, 10 μM), isoguvacine (a GABA A receptor agonist, 100 μM), dopamine (100 μM), and norepinephrine (100 μM). Biocytin injections coupled to aromatase immunocytochemistry identified 19 recorded neurons including 3 displaying a dense aromatase immunoreactivity. All of them responded to kainate, dopamine, and norepinephrine, while only one responded to isoguvacine and NMDA. Taken together, these results demonstrate a relative electrical and neurochemical homogeneity of the medial preoptic neurons, including a few aromatase-immunoreactive neurons that could be identified by immunocytochemistry after biocytin labeling of the recorded neurons.