Synaptic transmission and function of parasympathetic ganglia

Akasu, Takashi; Nishimura, Toshihiko

doi:10.1016/0301-0082(95)98602-2

Cited by 29 publications

(14 citation statements)

References 400 publications

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“…The safety factor for cholinergic neurotransmission appears to be high at intracardiac neurons that we studied since small increases in stimulation current evoked action potentials abruptly instead of first producing graded EPSPs (34). This finding is consistent with results reported for SAH cells of guinea-pig intracardiac ganglia (6) and for rat intracardiac neurons (35).…”

Section: Discussionsupporting

confidence: 90%

Tachykinin Agonists Modulate Cholinergic Neurotransmission at Guinea-Pig Intracardiac Ganglia

Zhang¹,

Hancock²,

Hoover³

2005

J Pharmacol Sci

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Abstract. Effects of substance P (SP) and selective tachykinin agonists on neurotransmission at guinea-pig intracardiac ganglia were studied in vitro. Voltage responses of neurons to superfused tachykinins and nerve stimulation were measured using intracellular microelectrodes. Predominant effects of SP (1 µM) were to cause slow depolarization and enable synaptic transmission at low intensities of nerve stimulation. Augmented response to nerve stimulation occurred with 29 of 40 intracardiac neurons (approx. 73%). SP inhibited synaptic transmission at 23% of intracardiac neurons but also caused slow depolarization. Activation of NK 3 receptors with 100 nM [MePhe 7 ]neurokinin B caused slow depolarization, enhanced the response of many intracardiac neurons to low intensity nerve stimulation or local application of acetylcholine, and triggered action potentials independent of other stimuli in 6 of 42 neurons. The NK 1 agonist [Sar 9,Met(O 2 ) 11 ]SP had similar actions but was less effective and did not trigger action potentials independently. Neither selective agonist inhibited cholinergic neurotransmission. We conclude that SP can function as a positive or negative neuromodulator at intracardiac ganglion cells, which could be either efferent neurons or interneurons. Potentiation occurs primarily through NK 3 receptors and may enable neuronal responses with less preganglionic nerve activity. Inhibition of neurotransmission by SP is most likely explained by the known blocking action of this peptide at ganglionic nicotine receptors.

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Section: Discussionsupporting

confidence: 90%

Tachykinin Agonists Modulate Cholinergic Neurotransmission at Guinea-Pig Intracardiac Ganglia

Zhang¹,

Hancock²,

Hoover³

2005

J Pharmacol Sci

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“…A threshold activation with OXO on muscarinic receptors may be antagonized by sympathetic transmission via ganglion nicotinic receptors (including a5 receptors) under normal conditions. Previous studies suggest that submandibular ganglia contributed to a higher safety factor for fast ganglionic post-synaptic transmission (f-EPSP) compared to other tissues, indicating that single preganglionic action potentials are more efficiently transmitted to the postganglionic neurons [21]. In the presence of a5 subunits, the receptors have a lower safety factor, modifying the postsynaptic potentials of sympathetic ganglia [6].…”

Section: Discussionmentioning

confidence: 99%

Nicotinic acetylcholine receptor α5 subunits modulate oxotremorine-induced salivation and tremor

Wang

Orr-Urtreger

Chapman

et al. 2004

Journal of the Neurological Sciences

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“…THE PARASYMPATHETIC CARDIAC PLEXUS integrates information from a variety of inputs, including sensory afferents, descending parasympathetic preganglionic fibers, sympathetic fibers, and interneurons (1,22). These ganglia consist of a heterogeneous population of cells, including postganglionic neurons and numerous interneurons (1,6,20,22).…”

mentioning

confidence: 99%

“…These ganglia consist of a heterogeneous population of cells, including postganglionic neurons and numerous interneurons (1,6,20,22). The convergence of inputs from such diverse sources allows these intracardiac neurons to rapidly respond to both central commands and local reflex circuits to regulate cardiac function.…”

mentioning

confidence: 99%

Ionic mechanisms of histamine-induced responses in guinea pig intracardiac neurons

Hardwick

Kotarski

Powers

2006

American Journal of Physiology-Regulatory, Integrative and Comp

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Histamine, released from mast cells, can modulate the activity of intrinsic neurons in the guinea pig cardiac plexus. The present study examined the ionic mechanisms underlying the histamine-induced responses in these cells. Histamine evokes a small membrane depolarization and an increase in neuronal excitability. Using intracellular voltage recording from individual intracardiac neurons, we were able to demonstrate that removal of extracellular sodium reduced the membrane depolarization, whereas inhibition of K+ channels by 1 mM Ba2+, 2 mM Cs+, or 5 mM tetraethylammonium had no effect. The depolarization was also not inhibited by either 10 microM Gd3+ or a reduced Cl- solution. The histamine-induced increase in excitability was unaffected by K+ channel inhibitors; however, it was reduced by either blockage of voltage-gated Ca2+ channels with 200 microM Cd2+ or replacement of extracellular Ca2+ with Mg2+. Conversely, alterations in intracellular calcium with thapsigargin or caffeine did not inhibit the histamine-induced effects. However, in cells treated with both thapsigargin and caffeine to deplete internal calcium stores, the histamine-induced increase in excitability was decreased. Treatment with the phospholipase C inhibitor U73122 also prevented both the depolarization and the increase in excitability. From these data, we conclude that histamine, via activation of H1 receptors, activates phospholipase C, which results in 1) the opening of a nonspecific cation channel, such as a transient receptor potential channel 4 or 5; and 2) in combination with either the influx of Ca2+ through voltage-gated channels or the release of internal calcium stores leads to an increase in excitability.

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Synaptic transmission and function of parasympathetic ganglia

Cited by 29 publications

References 400 publications

Tachykinin Agonists Modulate Cholinergic Neurotransmission at Guinea-Pig Intracardiac Ganglia

Tachykinin Agonists Modulate Cholinergic Neurotransmission at Guinea-Pig Intracardiac Ganglia

Nicotinic acetylcholine receptor α5 subunits modulate oxotremorine-induced salivation and tremor

Ionic mechanisms of histamine-induced responses in guinea pig intracardiac neurons

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