Morphology and electrophysiology of guinea‐pig paratracheal neurones

Lees, G.J.; Pacitti, Elaine G.; Mackenzie, Gillian M.

doi:10.1002/(sici)1097-0185(199702)247:2<261::aid-ar13>3.3.co;2-w

Cited by 4 publications

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“…1) and could be located without staining in most preparations. Furthermore, ganglia were distributed over the entire surface of the primary bronchus and not in separate plexuses, as reported for guinea pig (Lees et al, 1997;Canning and Fischer, 1997;Fischer et al, 1998), cat (Mitchell et al, 1989), dog (Yamamoto et al, 1998), and ferret (Coburn and Kalia, 1986;Dey et al, 1996;Dey et al, 1999) tracheal ganglia. Thus, the guinea pig bronchial nerve plexus provides an excellent preparation for characterization of physiological Myers, 1998), pharmacological Undem, 1993, 1996), and anatomical properties of parasympathetic innervation in smaller airways.…”

Section: Discussionsupporting

confidence: 62%

“…Results presented in this study describe the anatomical location and microscopic characteristics of neurons in parasympathetic ganglia on the primary bronchus of the guinea pig. Unlike in the guinea pig trachea, where the ganglia are located along smaller, irregular nerves (Baluk et al, 1985;Lees et al, 1997), bronchial ganglia were associated with larger peribronchial nerves ( Fig. 1) and could be located without staining in most preparations.…”

Section: Discussionmentioning

confidence: 85%

“…For example, phasic neurons in guinea pig bronchial parasympathetic ganglia respond to a prolonged suprathreshold stimulation with a high-frequency burst of action potentials and then cease action potential generation (i.e., accommodated), whereas tonic neurons are nonaccommodating and will respond with relatively lower frequency action potentials for as long as the stimulus was above threshold (Myers, 1998). Accommodative properties have also been determined for intrinsic ganglia neurons located in guinea pig (Lees et al, 1997) and rat (Allen and Burnstock, 1990) trachea, and a preliminary study identified tonic and phasic firing patterns in human bronchial parasympathetic ganglia neurons (Myers, 1997). In sympathetic ganglia, the tonic and phasic neurons appear to have different active and passive membrane properties (Griffith et al, 1980;Cassell et al, 1986) and have different anatomical characteristics as well (Boyd et al, 1996).…”

mentioning

confidence: 99%

“…Guinea pig lower airways have been extensively used to study airway hyperractivity and neuronal control of airway smooth muscle Dey, 1994). Based on the vital role played by smaller airways in regulating air flow to the lungs, it is therefore surprising that there have been no studies directly investigating the morphology of parasympathetic neurons in the guinea pig bronchi; studies hitherto in guinea pig (Baluk et al, 1985;Lees et al, 1997), rat (Chiang, 1993), ferret (Coburn and Kalia, 1986;Dey et al, 1996), cat (Mitchell et al, 1989), and dog (Yamamoto et al, 1998) have focused on neurons in tracheal ganglia. Thus, the purpose of this study was to determine the location and anatomical characteristics of bronchial parasympathetic ganglia neurons and to understand how these anatomical properties may relate and contribute to their integrative physiological function.…”

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confidence: 99%

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Anatomical characteristics of tonic and phasic postganglionic neurons in guinea pig bronchial parasympathetic ganglia

Myers

2000

J. Comp. Neurol.

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Anatomical characteristics of principal parasympathetic ganglia neurons on the guinea pig primary bronchus were analyzed, and the procedure for localizing the ganglia without the aid of staining for in vitro physiological studies is described. The neurons were tightly packed within a perineural sheath, and the cell bodies formed a homogeneous population based on size and shape. By using intracellular electrophysiological recordings, unstained neurons within these ganglia were characterized with suprathreshold depolarizing stimuli as having either accommodating action potential patterns (phasic neurons) or repetitive action potential patterns (tonic neurons). After determining whether a cell was tonic or phasic, it was injected with either horseradish peroxidase or Neurobiotin for characterization of its dendrites. There were no differences between tonic and phasic neurons, and both exhibited the following: (1) dendrites were multiple and branching; (2) all processes (axon and dendrites) arose from a circumscribed area on the somatic surface; (3) the initial direction of the processes was usually toward the center of the ganglion, creating a very dense intraganglionic neuropil; (4) tapering processes (presumed dendrites) extended beyond the border of the perineural sheath; and (5) many processes terminated with bouton-like swellings near the somatic surfaces of neighboring neurons within the same ganglion. Electron microscopic examination of dendritic and cell body membranes revealed that greater than 90% of the synapses occurred on dendrites. Based on immunohistochemical staining, all neurons were calbindin negative. These results indicate a relatively homogeneous population of neurons in bronchial parasympathetic ganglia displaying dendritic characteristics compatible with complex integrative properties.

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Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 85%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Anatomical characteristics of tonic and phasic postganglionic neurons in guinea pig bronchial parasympathetic ganglia

Myers

2000

J. Comp. Neurol.

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“…The phasic neurons fire during the inspiratory phase in vivo and primarily project to the tracheobronchial smooth muscles, whereas tonic neurons fire tonically during the inspiratory intervals and primarily project to the intercartilaginous space (Mitchell et al 1987). Postganglionic neurons with similar phasic or tonic firing properties have also been identified in vitro, both in humans and in animals (Baker, 1986;Myers et al 1990;Lees et al 1997;Myers, 1998). It is thus reasonable to postulate that the phasic postganglionic neurons are preferentially innervated by the IA-AVPNs in the eNA, whereas the tonic postganglionic neurons are preferentially innervated by the II-AVPNs in the eNA.…”

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Nicotine enhances both excitatory and inhibitory synaptic inputs to inspiratory‐activated airway vagal preganglionic neurons

Zhou

Chen

et al. 2012

Experimental Physiology

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New Findings r What is the central question of this study?Airway vagal preganglionic neurons (AVPNs) supply the essential excitatory drive to the postganglionic neurons, which dominate the neural control of the airway physiologically and play critical roles in the pathogenesis of some common airway disorders. AVPNs express multiple subunits of nicotinic acetylcholine receptors (nAChRs), but the influences of exogenous nicotine or endogenous acetylcholine are unknown. r What is the main finding and its importance?Nicotine and endogenous acetylcholine both cause a postsynaptic excitatory current in inspiratory-activated AVPNs, and enhance both the excitatory and inhibitory synaptic inputs. The overall effect of nicotine on inspiratory-activated AVPNs is excitatory. The nicotinic effects on inspiratory-activated AVPNs are mediated presynaptically by activation of α4β2 type of nAChRs and postsynaptically by activation of multiple nAChRs including α7 and α4β2 types.The airway vagal preganglionic neurons (AVPNs) supply the essential excitatory drive to the postganglionic neurons and dominate the neural control of the airway both physiologically and pathophysiologically. The AVPNs express multiple subunits of nicotinic acetylcholine receptors (nAChRs), but the influences of exogenous nicotine and endogenous acetylcholine are unknown. This study examined the effects of nicotine and endogenous acetylcholine on retrogradely labelled, functionally identified inspiratory-activated AVPNs (IA-AVPNs) using the patchclamp technique. Nicotine (10 μmol l −1 ) significantly increased the frequency and amplitude of the spontaneous EPSCs of IA-AVPNs, and these effects were insensitive to methyllycaconitine (MLA, 100 nmol l −1 ), an antagonist of the α7 type of nAChR, but was prevented by dihydro-β-erythroidine (DHβE, 3 μmol l −1 ), an antagonist of the α4β2 type of nAChR. Nicotine caused a tonic inward current in IA-AVPNs, which was reduced by MLA or DHβE alone, but was not abolished by co-application of MLA and DHβE. Nicotine caused a significant increase in the frequency of GABAergic and glycinergic spontaneous IPSCs and significantly increased the amplitude of glycinergic spontaneous IPSCs, all of which were prevented by DHβE. Nicotine had no effects on the miniature EPSCs or miniature IPSCs following pretreatment with TTX. Under current clamp, nicotine caused depolarization and increased the firing rate of IA-AVPNs during inspiratory intervals. Neostigmine (10 μmol l −1 ), an acetylcholinesterase inhibitor, mimicked the effects of nicotine. These results demonstrate that nicotine and endogenous ACh enhance the excitatory and inhibitory synaptic inputs of IA-AVPNs and cause a postsynaptic excitatory

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Anatomical characteristics of tonic and phasic postganglionic neurons in guinea pig bronchial parasympathetic ganglia

Myers

2000

J. Comp. Neurol.

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Anatomical characteristics of principal parasympathetic ganglia neurons on the guinea pig primary bronchus were analyzed, and the procedure for localizing the ganglia without the aid of staining for in vitro physiological studies is described. The neurons were tightly packed within a perineural sheath, and the cell bodies formed a homogeneous population based on size and shape. By using intracellular electrophysiological recordings, unstained neurons within these ganglia were characterized with suprathreshold depolarizing stimuli as having either accommodating action potential patterns (phasic neurons) or repetitive action potential patterns (tonic neurons). After determining whether a cell was tonic or phasic, it was injected with either horseradish peroxidase or Neurobiotin for characterization of its dendrites. There were no differences between tonic and phasic neurons, and both exhibited the following: (1) dendrites were multiple and branching; (2) all processes (axon and dendrites) arose from a circumscribed area on the somatic surface; (3) the initial direction of the processes was usually toward the center of the ganglion, creating a very dense intraganglionic neuropil; (4) tapering processes (presumed dendrites) extended beyond the border of the perineural sheath; and (5) many processes terminated with bouton‐like swellings near the somatic surfaces of neighboring neurons within the same ganglion. Electron microscopic examination of dendritic and cell body membranes revealed that greater than 90% of the synapses occurred on dendrites. Based on immunohistochemical staining, all neurons were calbindin negative. These results indicate a relatively homogeneous population of neurons in bronchial parasympathetic ganglia displaying dendritic characteristics compatible with complex integrative properties. J. Comp. Neurol. 419:439–450, 2000. © 2000 Wiley‐Liss, Inc.

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Morphology and electrophysiology of guinea‐pig paratracheal neurones

Cited by 4 publications

References 0 publications

Anatomical characteristics of tonic and phasic postganglionic neurons in guinea pig bronchial parasympathetic ganglia

Anatomical characteristics of tonic and phasic postganglionic neurons in guinea pig bronchial parasympathetic ganglia

Nicotine enhances both excitatory and inhibitory synaptic inputs to inspiratory‐activated airway vagal preganglionic neurons

Anatomical characteristics of tonic and phasic postganglionic neurons in guinea pig bronchial parasympathetic ganglia

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