QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (29) Citing Articles via Google Scholar Google Scholar Articles by Williams, S. Articles by Bernheim, L. Search for Related Content PubMed PubMed Citation Articles by Williams, S. Articles by Bernheim, L.

 Previous Article  |  Next Article 

Volume 17, Number 19, Issue of October 1, 1997 pp. 7307-7315
Copyright ©1997 Society for Neuroscience

Distinct Contributions of High- and Low-Voltage-Activated Calcium Currents to Afterhyperpolarizations in Cholinergic Nucleus Basalis Neurons of the Guinea Pig

Received Jan. 21, 1997; revised July 18, 1997; accepted July 22, 1997.

Sylvain Williams, Mauro Serafin, Michel Mühlethaler, and Laurent Bernheim

Département de Physiologie, Centre Médical Universitaire, 1211 Genève 4, Switzerland

The contributions made by low- (LVA) and high-voltage-activated (HVA) calcium currents to afterhyperpolarizations (AHPs) of nucleus basalis (NB) cholinergic neurons were investigated in dissociated cells. Neurons with somata >25 µM were studied because 80% of them stained positively for choline acetyltransferase and had electrophysiological characteristics identical to those of cholinergic NB neurons previously recorded in basal forebrain slices. Calcium currents of cholinergic NB neurons first were dissected pharmacologically into an amiloride-sensitive LVA and at least five subtypes of HVA currents. Approximately 17% of the total HVA current was sensitive to nifedipine (3 µM), 35% to -conotoxin-GVIA (200-400 nM), 10% to -Agatoxin-IVA (100 nM), and 20% to -Agatoxin-IVA (300-500 nM), suggesting the presence of L-, N-, P-, and Q-type channels, respectively. A remaining current (R-type) resistant to these antagonists was blocked by cadmium (100-200 µM). We then assessed pharmacologically the role that LVA and HVA currents had in activating the apamin-insensitive AHP elicited by a long train of action potentials (sAHP) and the AHP evoked either by a short burst of action potentials or by a single action potential (mAHP) that is known to be apamin-sensitive. During sAHPs, ~60% of the hyperpolarization was activated by calcium flowing through N-type channels and ~20% through P-type channels, whereas T-, L-, and Q-type channels were not involved significantly. In contrast, during mAHPs, N- and T-type channels played key roles (~60 and 30%, respectively), whereas L-, P-, and Q-type channels were not implicated significantly. It is concluded that in cholinergic NB neurons various subtypes of calcium channels can differentially activate the apamin-sensitive mAHP and the apamin-insensitive sAHP.

Key words: acetylcholine; afterhyperpolarization; arousal; basal forebrain; calcium currents; low-threshold spike

This article has been cited by other articles:

				D. Murchison, A. N. McDermott, C. L. LaSarge, K. A. Peebles, J. L. Bizon, and W. H. Griffith Enhanced Calcium Buffering in F344 Rat Cholinergic Basal Forebrain Neurons Is Associated With Age-Related Cognitive Impairment J Neurophysiol, October 1, 2009; 102(4): 2194 - 2207. [Abstract] [Full Text] [PDF]

				S. A. Prescott and T. J. Sejnowski Spike-Rate Coding and Spike-Time Coding Are Affected Oppositely by Different Adaptation Mechanisms J. Neurosci., December 10, 2008; 28(50): 13649 - 13661. [Abstract] [Full Text] [PDF]

				X. Li and D. J. Bennett Apamin-Sensitive Calcium-Activated Potassium Currents (SK) Are Activated by Persistent Calcium Currents in Rat Motoneurons J Neurophysiol, May 1, 2007; 97(5): 3314 - 3330. [Abstract] [Full Text] [PDF]

				Y. Yaari, C. Yue, and H. Su Recruitment of apical dendritic T-type Ca2+ channels by backpropagating spikes underlies de novo intrinsic bursting in hippocampal epileptogenesis J. Physiol., April 15, 2007; 580(2): 435 - 450. [Abstract] [Full Text] [PDF]

				M. Kato, N. Tanaka, S. Usui, and Y. Sakuma The SK channel blocker apamin inhibits slow afterhyperpolarization currents in rat gonadotropin-releasing hormone neurones J. Physiol., July 15, 2006; 574(2): 431 - 442. [Abstract] [Full Text] [PDF]

				J. A. Goldberg and C. J. Wilson Control of Spontaneous Firing Patterns by the Selective Coupling of Calcium Currents to Calcium-Activated Potassium Currents in Striatal Cholinergic Interneurons J. Neurosci., November 2, 2005; 25(44): 10230 - 10238. [Abstract] [Full Text] [PDF]

				M. Russier, E. Carlier, N. Ankri, L. Fronzaroli, and D. Debanne A-, T-, and H-type Currents Shape Intrinsic Firing of Developing Rat Abducens Motoneurons J. Physiol., May 15, 2003; 549(1): 21 - 36. [Abstract] [Full Text] [PDF]

				R. K. Cloues and W. A. Sather Afterhyperpolarization Regulates Firing Rate in Neurons of the Suprachiasmatic Nucleus J. Neurosci., March 1, 2003; 23(5): 1593 - 1604. [Abstract] [Full Text] [PDF]

				E. Perez-Reyes Molecular Physiology of Low-Voltage-Activated T-type Calcium Channels Physiol Rev, January 1, 2003; 83(1): 117 - 161. [Abstract] [Full Text] [PDF]

				M. R. Smith, A. B. Nelson, and S. du Lac Regulation of Firing Response Gain by Calcium-Dependent Mechanisms in Vestibular Nucleus Neurons J Neurophysiol, April 1, 2002; 87(4): 2031 - 2042. [Abstract] [Full Text] [PDF]

				P. Cavelier, F. Pouille, T. Desplantez, H. Beekenkamp, and J.-L. Bossu Control of the propagation of dendritic low-threshold Ca2+ spikes in Purkinje cells from rat cerebellar slice cultures J. Physiol., April 1, 2002; 540(1): 57 - 72. [Abstract] [Full Text] [PDF]

				J. Martinez-Pinna, P. J. Davies, and E. M. McLachlan Diversity of Channels Involved in Ca2+ Activation of K+ Channels During the Prolonged AHP in Guinea-Pig Sympathetic Neurons J Neurophysiol, September 1, 2000; 84(3): 1346 - 1354. [Abstract] [Full Text] [PDF]

				M. Shah and D. G. Haylett Ca2+ Channels Involved in the Generation of the Slow Afterhyperpolarization in Cultured Rat Hippocampal Pyramidal Neurons J Neurophysiol, May 1, 2000; 83(5): 2554 - 2561. [Abstract] [Full Text] [PDF]

				T G J Allen The role of N-, Q- and R-type Ca2+ channels in feedback inhibition of ACh release from rat basal forebrain neurones J. Physiol., February 15, 1999; 515(1): 93 - 107. [Abstract] [Full Text] [PDF]

				M. Tanabe, B. H. Gahwiler, and U. Gerber L-Type Ca2+ Channels Mediate the Slow Ca2+-Dependent Afterhyperpolarization Current in Rat CA3 Pyramidal Cells In Vitro J Neurophysiol, November 1, 1998; 80(5): 2268 - 2273. [Abstract] [Full Text] [PDF]

				J. C. Pineda, R. S. Waters, and R. C. Foehring Specificity in the Interaction of HVA Ca2+ Channel Types With Ca2+-Dependent AHPs and Firing Behavior in Neocortical Pyramidal Neurons J Neurophysiol, May 1, 1998; 79(5): 2522 - 2534. [Abstract] [Full Text] [PDF]

				P. Cavelier, F. Pouille, T. Desplantez, H. Beekenkamp, and J.-L. Bossu Control of the propagation of dendritic low-threshold Ca2+ spikes in Purkinje cells from rat cerebellar slice cultures J. Physiol., April 1, 2002; 540(1): 57 - 72. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help