Substance P produces an inward current by suppressing voltage-dependent and -independent K+ currents in bullfrog primary afferent neurons

Ishimatsu, Masaru

doi:10.1016/0168-0102(94)90003-5

Cited by 20 publications

(22 citation statements)

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“…Indirect evidence for SP autoreceptors already exists. Some guineapig trigeminal ganglion neurones and bullfrog dorsal root ganglion neurones are depolarized by exogenous application of SP (Dray & Pinnock, 1982;Spigelman & Puil, 1990;Ishimatsu, 1994). Many vagal primary afferent neurones (nodose and jugular ganglion neurones) of numerous species have been immunocytochemically shown to contain SP (Katz & Karten, 1980;Kummer, Fischer, Kurkowski & Heym, 1992; and see review by Otsuka & Yoshioka, 1993).…”

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confidence: 99%

Substance P hyperpolarizes vagal sensory neurones of the ferret.

Jafri

Weinreich

1996

The Journal of Physiology

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1. Intracellular recordings were made in intact and in acutely dissociated vagal afferent neurones (nodose ganglion cells) of the ferret to investigate the effects of substance P (SP). 2. In current-clamp recordings, SP (100 nM) applied by superfusion hyperpolarized the membrane potential (7 + 0 7 mV; mean + S.E.M.; n = 105) and decreased the input resistance in 80 % of the neurones. With voltage-clamp recording, SP produced an outward current of 3 + 0-2 nA (n = 10). 3. The SP current was concentration dependent with an estimated EC50 of 68 nm. The SP-induced hyperpolarization or current was mimicked by the tachykinin receptor NK1agonist Ac-[Arg6, Sar9, Met(02)'1]SP(6-1 1) (ASM-SP; 100 nM; n = 10) and blocked by the NK1 antagonist CP-96,345 (10 nM; n = 6), but not by the NK2 antagonist SR48968(100 nM; n = 4). No measurable change in membrane potential or input resistance was observed with application of either [/J-Ala8]neurokinin A or senktide, selective NK2 and NK3 receptor agonists, respectively (100 nM; n = 3 for each agonist).4. The reversal potential (Erev) for the SP outward current was -85 + 2-5 mV (n = 4). The Erev for the SP response shifted in a Nernstian manner with changes in extracellular potassium concentration. Alterations in extracellular sodium or chloride concentrations had no significant effect on the E for the SP response (n = 3 for each ion).5. Nominally Ca2+-free external solution abolished the SP response. Removal of magnesium from the extracellular solution had no effect on the response.6. Caesium (100 /,M), barium (1 mM), tetraethylammonium (TEA; 5 mm), apamin (10 nM) and 4-aminopyridine (4-AP; 4 mm) each completely prevented the SP response (n > 3 for each).7. These results indicate that SP, via an NK1 receptor, can induce a Ca2+-dependent outward potassium current which hyperpolarizes the resting membrane potential of vagal afferent somata.

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confidence: 99%

Substance P hyperpolarizes vagal sensory neurones of the ferret.

Jafri

Weinreich

1996

The Journal of Physiology

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“…1A). (Ishimatsu, 1994;Akasu et al 1996), bath application of SP (1 ,UM) did not elicit the inward current (Akasu et al 1996) but consistently depressed IGABA in the modified Ringer solution. EGABA was -2 + 1 mV (n = 12) and 0'4 + 1 mV (n = 6) in the absence and presence, respectively, of SP (1 ,4M).…”

Section: Whole-cell Recordingsmentioning

confidence: 99%

“…To avoid 'run-down' of IGABA during the wholecell recordings, the internal solution contained adenosine 5'-triphosphate sodium (Na2-ATP, 5 mm) (Chen et al 1990; Shirasaki, Aibara & Akaike, 1992;Gyenes et al 1994 (Ishimatsu, 1994;Akasu et al 1996). The amplitude of IGABA was depressed by 100 nM SP (Fig.…”

Section: Whole-cell Recordingsmentioning

confidence: 99%

“…SP causes enhancement or depression of the noxious response by modifying both the release of a sensory transmitter and the excitability of the postsynaptic membrane in substantia gelatinosa cells of the cat dorsal horn (Zieglgiinsberger & Tulloch, 1979;Davies & Dray, 1980;Murase, Nedeljkov & Randic, 1982). Application of SP to neurones of the dorsal root ganglia (DRG) produced a depolarizing response associated with an increase in neuronal excitability (Dray & Pinnock, 1982;Ishimatsu, 1994). Recent studies showed that SP and neurokinin A (NKA) cause an inward current by suppressing K+ conductances through a guanine nucleotide-binding protein (G-protein) in dissociated DRG neurones of bullfrogs (Ishimatsu, 1994; Akasu, Ishimatsu & Yamada, 1996).…”

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confidence: 99%

“…Application of SP to neurones of the dorsal root ganglia (DRG) produced a depolarizing response associated with an increase in neuronal excitability (Dray & Pinnock, 1982;Ishimatsu, 1994). Recent studies showed that SP and neurokinin A (NKA) cause an inward current by suppressing K+ conductances through a guanine nucleotide-binding protein (G-protein) in dissociated DRG neurones of bullfrogs (Ishimatsu, 1994; Akasu, Ishimatsu & Yamada, 1996). y-Aminobutyric acid (GABA) is the primary inhibitory transmitter in the spinal cord, which causes a reduction of the release of excitatory transmitter from primary afferent nerve terminals, termed 'presynaptic inhibition' (Eccles, 1964).…”

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confidence: 99%

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Substance P suppresses GABAA receptor function via protein kinase C in primary sensory neurones of bullfrogs.

Yamada

Akasu

1996

The Journal of Physiology

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Central Mechanisms I: Plasticity of Central Pathways

Chen

Joad

Bric

et al. 2009

Pharmacology and Therapeutics of Cough

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Cough is the most common symptom for which individuals seek medical attention and spend health-care dollars. Despite the burden induced by cough, the current treatments for cough are only partially effective. Delineating the sites and mechanisms in the cough central network for changes in the cough reflex could lead to new therapeutic strategies and drug target sites for more effective treatments. The first synaptic target in the CNS for the cough-related sensory input is the second-order neurons in the nucleus tractus solitarius (NTS); these neurons reorganize the primary sensory information into a coherent output. The NTS neurons have been shown to undergo neuroplasticity under a variety of conditions, such as respiratory disorders, stress, and exposures to environmental pollutants. The NTS contains a rich innervation of substance P immunoreactive nerve terminals, suggesting that substance P might be important in altered cough reflex response. This chapter summarizes our current findings on the role of substance P in enhanced cough reflex as well as the potential NTS targets for the action of substance P.

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Substance P produces an inward current by suppressing voltage-dependent and -independent K+ currents in bullfrog primary afferent neurons

Cited by 20 publications

References 35 publications

Substance P hyperpolarizes vagal sensory neurones of the ferret.

Substance P hyperpolarizes vagal sensory neurones of the ferret.

Substance P suppresses GABAA receptor function via protein kinase C in primary sensory neurones of bullfrogs.

Central Mechanisms I: Plasticity of Central Pathways

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