Sites of transmitter release and relation to intracellular Ca2+ in cultured sympathetic neurons

Przywara, Dennis A.; Bhave, Sanjiv V.; Chowdhury, Pertha S.; Wakade, Taruna D.; Wakade, Arun R.

doi:10.1016/0306-4522(93)90544-p

Cited by 42 publications

(17 citation statements)

References 30 publications

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“…The lectin reduced electrically evoked [3HI NA release from chick sympathetic neurons in a concentration-dependent manner with half-maximal effects at 0.16 1.tM. This effect arose at a presynaptic site of action, as evidenced by the following data: (a) Sites of transmitter release in primary cultures of chick sympathetic neurons are located exclusively at axons and axon terminals, and not at the somatodendritic region (Przywara et al, 1993). (b) Neither the resting membrane potential nor action potentials that link electrical stimuli to the Ca 2-dependent release of NA [as indicated by tetrodotoxin sensitivity (e.g., 1 were altered by ConA.…”

Section: Discussionmentioning

confidence: 83%

“…Despite the multitude of different effects ConA exerts at postsynaptic sites, just one prominent action of this lectin has been described at presynaptic specializations: ConA prevents transmitter release evoked by a-an experimental model to investigate mechanisms of transmitter release, in particular presynaptic modulation (for review, see Boehm and Huck, 1997a). These neurons release noradrenaline (NA) exclusively at growth cones and/or axon terminals, but not at neuronal somata (Przywara et al, 1993). NA release from these presynaptic specializations can be induced by action potentials triggered via electrical field stimulation, by K~depolarization, by Ca 2~ionophores, and by a-latrotoxin .…”

Section: Primary Cultures Of Chick Sympathetic Neurons Providementioning

confidence: 99%

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Presynaptic Inhibition by Concanavalin A: Are α‐Latrotoxin Receptors Involved in Action Potential‐Dependent Transmitter Release?

Boehm

Huck

1998

Journal of Neurochemistry

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Abstract:Effects of concanavalin A on transmitter release were investigated in primary cultures of chick sympathetic neurons. The lectin reduced electrically evoked [ 3H]noradrenaline release by up to 30% with half-maximal inhibition at 0.16 bLM. Concanavalin A also reduced the release triggered by extracellular Ca2~in neurons depolarized by 25 mM Kõr rendered Ca2-permeable by the ionophore A231 87. The inhibitory action of concanavaIm A on electrically evoked release was additive to that of the a 2-adrenergic agonist UK 14,304. Inactivation of Gãnd GIG0 type G proteins by either cholera or pertussis toxin did not alter the inhibitory effect of the lectin. Concanavalin A failed to affect the resting membrane potential, action potential waveforms, or voltage-dependent K~and Ca 2~currents. In contrast, the lectin efficiently blocked both the Ca2-dependent and -independent alatrotoxin-induced transmitter release, but only when applied before the toxin. The reduction of electrically evoked, as well as a-latrotoxin-evoked, release by concanavalin A was attenuated in the presence of glucose and abolished by methyl a-D-mannopyranoside. The dimeric derivative, succinyl-concanavalin A, was significantly less active than tetrameric concanavalin A. In bovine adrenal chromaffin cells, which displayed only weak secretory responses to a-latrotoxin, concanavalin A failed to alter K~-evokedcatecholamine secretion. These results show that concanavalin A causes presynaptic inhibition in sym pathetic neurons and indicate that cross-linking of a-latrotoxin receptors may reduce action potential-dependent transmitter release. Key Words: Concanavalin A-a-Latrotoxin-Noradrenaline release-Chick sympathetic neurons-Bovine chromaffin cells-Presynaptic inhibition.

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Section: Discussionmentioning

confidence: 83%

Section: Primary Cultures Of Chick Sympathetic Neurons Providementioning

confidence: 99%

Presynaptic Inhibition by Concanavalin A: Are α‐Latrotoxin Receptors Involved in Action Potential‐Dependent Transmitter Release?

Boehm

Huck

1998

Journal of Neurochemistry

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“…Likewise, in SCG growth cones, which might be a model for terminals, Ca 2ϩ influx measured by a Ca 2ϩ indicator is greatly attenuated by -conotoxin GVIA but much less by 30 M nifedipine (21). Nevertheless, single channel and whole cell recordings do reveal some L-type channels along with the N-type channels in both the cell body and in the growth cones (29,(37)(38)(39).…”

Section: Discussionmentioning

confidence: 99%

Modulation by neurotransmitters of catecholamine secretion from sympathetic ganglion neurons detected by amperometry

Koh

Hille

1997

Proc. Natl. Acad. Sci. U.S.A.

108

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Many neuromodulators inhibit N-type Ca 2؉ currents via G protein-coupled pathways in acutely isolated superior cervical ganglion (SCG) neurons. Less is known about which neuromodulators affect release of norepinephrine (NE) at varicosities and terminals of these neurons. To address this question, we used carbon fiber amperometry to measure catecholamine secretion evoked by electrical stimulation at presumed sites of high terminal density in cultures of SCG neurons. The pharmacological properties of action potential-evoked NE release paralleled those of N-type Ca 2؉ channels: Release was completely blocked by Cd 2؉ or -conotoxin GVIA, reduced 50% by 10 M NE or 62% by 2 M UK-14,304, an ␣ 2 -adrenergic agonist, and reduced 63% by 10 M oxotremorine M (Oxo-M), a muscarinic agonist. Consistent with action at M 2 or M 4 receptor subtypes, Oxo-M could be antagonized by 10 M muscarinic antagonists methoctramine and tropicamide but not by pirenzepine. After overnight incubation with pertussis toxin, inhibition by UK-14,304 and Oxo-M was much reduced. Other neuromodulators known to inhibit Ca 2؉ channels in these cells, including adenosine, prostaglandin E 2 , somatostatin, and secretin, also depressed secretion by 34-44%. In cultures treated with -conotoxin GVIA, secretion dependent on L-type Ca 2؉ channels was evoked with long exposure to high K ؉ Ringer's solution. This secretion was not sensitive to UK-14,304 or Oxo-M. Evidently, many neuromodulators act on the secretory terminals of SCG neurons, and the depression of NE release at terminals closely parallels the membrane-delimited inhibition of N-type Ca 2؉ currents in the soma.Patch-clamp technique studies have shown that N-type Ca 2ϩ channels of the cell soma are modulated via many different G protein-coupled neurotransmitter receptors in superior cervical ganglion (SCG) neurons (1-6; for review, see ref. 7). Many neurotransmitter receptors, including ␣ 2 -adrenergic, somatostatin, prostaglandin E 2 (PGE 2 ), adenosine, M 4 muscarinic, pancreatic polypeptide, secretin, vasoactive intestinal peptide, and substance P, inhibit by a fast, membrane-delimited mechanism (7). Angiotensin II receptors and M 1 muscarinic receptors inhibit Ca 2ϩ channels via a slow, diffusible cytoplasmic messenger.Despite intensive work dissecting different modulatory pathways and investigating their underlying mechanisms (7-9), definite physiological roles for Ca 2ϩ channel inhibition in SCG cells have not yet been determined. Two have been proposed (7, 10): (i) In the soma, inhibition of Ca 2ϩ entry could alter cell excitability and action potential firing patterns because the somata possess Ca 2ϩ -activated K ϩ channels and Ca 2ϩ -sensitive M-type K ϩ channels (11-13), and (ii) at sympathetic nerve terminals and varicosities, inhibition of Ca 2ϩ influx could decrease norepinephrine (NE) secretion, as in Dunlap and Fischbach's (14) general concept of presynaptic inhibition. This hypothesis would require that N-type Ca 2ϩ channels be functionally coupled to many receptors at the dist...

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“…The release-inhibiting P2-receptors share some properties with cloned and expressed P2Y1-receptors (for references see above), but their molecular identity is yet not known. In addition to inhibitory P2-receptors, the cell bodies of postganglionic sympathetic neurons, adrenal chromaffin cells, and PC12 cells possess excitatory P2-receptors of distinct subtypes and with distinct signaling transduction pathways (for reviews see Silinsky et al, 1998;von Kü gelgen et al, 1999a; for PC12 cells see, for example, Arslan et al, 2000;Unterberger et al, 2002).The inhibition of calcium channels at axon terminals is a key element in the modulation of transmitter release by inhibitory G-protein-coupled receptors (see Przywara et al, 1993;Mirotznik et al, 2000;Jarvis and Zamponi, 2001). Therefore, we searched for P2-receptors modulating the elecThis work was supported by the Doktor Robert Pfleger Stiftung (Bamberg, Germany).…”

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confidence: 99%

P2Y-Receptors Mediating an Inhibition of the Evoked Entry of Calcium through N-Type Calcium Channels at Neuronal Processes

Kulick¹,

Kügelgen²

2002

J Pharmacol Exp Ther

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In the search for P2-receptors modulating the stimulation-evoked entry of calcium at processes of PC12 cells differentiated in the presence of nerve growth factor and neurotrophin-3, electrically evoked increases in free calcium were assessed by fura-2 microfluorimetry. Omission of calcium and addition of cadmium (100 M) or the N-type calcium channel blocker -conotoxin GVIA (0.5 M) abolished or markedly reduced the evoked responses. The P2Y-receptor agonists 2-methylthio adenosine 5Ј-diphosphate (2-methylthio-ADP), ADP, and adenosine 5Ј-O-(2-thiodiphosphate) (ADP␤S) inhibited the electrically evoked entry of calcium without any changes in basal calcium concentrations. 2-Methylthio-ADP was the most potent agonist. Adenosine, P -methyl-2Ј-deoxyadenosine 3Ј,5Ј-bisphosphate; 10 M), as well as the adenosine A 1 -receptor antagonist DPCPX (8-cyclopentyl-1,3-dipropylxanthine; 100 nM), caused no change. Pretreatment with pertussis toxin abolished the effect of ADP␤S. Reverse transcriptase-polymerase chain reaction revealed the presence of mRNA for P2Y12-receptors in nondifferentiated and differentiated PC12 cells. The results indicate that processes of differentiated PC12 cells possess P2Y12-receptors coupling to pertussis toxin-sensitive G-proteins and mediating an inhibition of the stimulation-evoked entry of calcium through -conotoxin GVIA-sensitive calcium channels. This suggests a role of P2Y12-receptors in neuromodulation in addition to their involvement in platelet aggregation.The operation of P2-receptors inhibiting the release of neurotransmitters has been demonstrated in the peripheral and central nervous system (for reviews see Silinsky et al., 1998;Inoue et al., 1999;von Kü gelgen et al., 1999a). At postganglionic sympathetic axons the receptors are activated by endogenous adenine nucleotides released as cotransmitters of norepinephrine and, hence, mediate a negative feedback inhibition of sympathetic transmitter release (Fuder and Muth, 1993;von Kü gelgen et al., 1993). Release-inhibiting P2-receptors have also been found in adrenal chromaffin cells and the cell bodies of rat PC12 cells (Gandia et al., 1993;Currie and Fox, 1996;Powell et al., 2000;Vartian and Boehm, 2001;Unterberger et al., 2002). The release-inhibiting P2-receptors share some properties with cloned and expressed P2Y1-receptors (for references see above), but their molecular identity is yet not known. In addition to inhibitory P2-receptors, the cell bodies of postganglionic sympathetic neurons, adrenal chromaffin cells, and PC12 cells possess excitatory P2-receptors of distinct subtypes and with distinct signaling transduction pathways (for reviews see Silinsky et al., 1998;von Kü gelgen et al., 1999a; for PC12 cells see, for example, Arslan et al., 2000;Unterberger et al., 2002).The inhibition of calcium channels at axon terminals is a key element in the modulation of transmitter release by inhibitory G-protein-coupled receptors (see Przywara et al., 1993;Mirotznik et al., 2000;Jarvis and Zamponi, 2001). Therefore, we searched for...

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Sites of transmitter release and relation to intracellular Ca2+ in cultured sympathetic neurons

Cited by 42 publications

References 30 publications

Presynaptic Inhibition by Concanavalin A: Are α‐Latrotoxin Receptors Involved in Action Potential‐Dependent Transmitter Release?

Presynaptic Inhibition by Concanavalin A: Are α‐Latrotoxin Receptors Involved in Action Potential‐Dependent Transmitter Release?

Modulation by neurotransmitters of catecholamine secretion from sympathetic ganglion neurons detected by amperometry

P2Y-Receptors Mediating an Inhibition of the Evoked Entry of Calcium through N-Type Calcium Channels at Neuronal Processes

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