K+ channels of expiratory neurones in the brain stem preparation of the newborn rat.
Single channel activity of expiratory neurones was studied in outside-out recordings. Expiratory neurones were identified in the ventrolateral region of the in vitro isolated brain stem-spinal cord preparation of newborn rats in cell-attached and whole-cell configurations by their pattern of firing related to phrenic motor output. Three potassium (K+) channels of 10, 30 and 70 pS exhibited steady-state activity during long voltage commands (up to 5 min) and could be found associated together in the same patches. The 30pS channel showed voltage dependency, being most active at small depolarizations. The 70 pS channel showed little activity with < 1% of openings per sample time and 1 mM tetraethylammonium (TEA) sensitivity. At similar concentrations, the discharge of the phrenic nerve was also altered, as shown by the increase of the respiratory frequency and a tonic discharge. The association of these K+ channel types on the same patches may be specific of respiratory neurones and could contribute to their bursting activity.
Jacquin
T D
TD
Laboratoire de biologie fonctionnelle du neurone, CNRS, Institut Alfred Fessard, Gif sur Yvette, France.
Descoins
C
C
Champagnat
J
J
Denavit-Saubie
M
M
D000818:Animals; D000831:Animals, Newborn; D001933:Brain Stem / Q000502:physiology*; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D008526:Medulla Oblongata / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010791:Phrenic Nerve / Q000502:physiology*; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D019789:Tetraethylammonium / Q000494:pharmacology
D015221:Potassium Channels; D019789:Tetraethylammonium