Whole cell recordings from acutely dissociated septal neurons.

Electrophysiological studies have been performed on cultured neurons isolated from the fetal (or newborn) rat or mouse central nervous system (CNS) (Barker and Ransom, 1978a, b; Mathers and Barker, 1980). Recently, several reports have appeared describing the electrophysiologi cal properties of acutely dissociated neurons from the adult mammalian CNS (Kay and Wong, 1986; Kiskin et al. 1986a, b; Akaike and Kaneda, 1989). In this study, single neurons were isolated from the dorsolateral region of the rat septal slice preparation. Resting and action potentials of acutely dissociated septal neurons had characteristics similar to the potentials in intact neurons in septal slice preparations. Adult (2-4 weeks) male Wister rats, weighing 100-150 g, were decapitated and the brain including the septal regions was rapidly sliced at a thickness of 500ƒÊm (Stevens et al. 1984). The slices were maintained in an oxygenated artificial cerebrospinal fluid (A CSF) of the following composition (mM) : NaCl, 117; KCI, 4.7 ; CaC12, 2.5; MgC12, 1.2; NaH2PO4, 1.6; NaHCO3, 25 and glucose, 10. After incubation of the slices for 30-40 min inA-CSF at room temperature, the slices were en zymatically treated in A-CSF containing 0.05% collagenase and 0.1 % trypsin (type Xl) bubbled with 95% O2, 5% C02 at 37•Ž for 60-90 min . The enzyme treatment was halted by washing with A CSF twice, the slices were then placed in a glass Petri dish filled with A CSF, and the septal regions were manually removed from the slice using a blade. The isolated regions were cut with a blade into fragments of about 3 mm square. The fragments were