Abstract
1. Isolated rat dorsal root ganglia (DRG) neurones support vesicular, non synaptic release of substance P in a depolarisation and Ca2+ dependent manner. 2. In vivo this process may mediate cross-communication between DRG cells in some neuropathological conditions and is therefore a putative area for drug intervention. 3. The authors investigated the voltage-dependent Ca2+ channel (VDCC) subtypes involved in somatic release of substance P. Fresh (< 1 day) cultures of DRG neurones were incubated with high K+ depolarising saline in the presence and absence of subtype selective VDCC blockers. Substance P released into the external media was collected and quantified using a radioimmunoassay. 4. The results show that L-type and N-type, but not P-type, VDCCs play an important role in high K+ evoked substance P release from rat DRG neurones.
MeSH terms
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Animals
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Calcium Channel Blockers / pharmacology
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Calcium Channels / drug effects
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Calcium Channels / physiology*
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Calcium Channels, L-Type / drug effects
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Calcium Channels, N-Type / drug effects
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Calcium Channels, P-Type / drug effects
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Electrophysiology
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Female
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Ganglia, Spinal / cytology
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Ganglia, Spinal / metabolism
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Ganglia, Spinal / ultrastructure
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Immunohistochemistry
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In Vitro Techniques
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Ion Channel Gating / drug effects
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Ion Channel Gating / physiology*
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Male
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Microscopy, Electron
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Neurons / drug effects
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Neurons / metabolism
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Neurons / ultrastructure
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Peripheral Nervous System / drug effects
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Peripheral Nervous System / metabolism*
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Potassium / pharmacology
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Rats
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Rats, Sprague-Dawley
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Substance P / metabolism*
Substances
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Calcium Channel Blockers
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Calcium Channels
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Calcium Channels, L-Type
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Calcium Channels, N-Type
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Calcium Channels, P-Type
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Substance P
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Potassium