Nov 15, 2006

Two types of neurotransmitter release patterns in isolectin B4-positive and negative trigeminal ganglion neurons

Y MatsukaI Spigelman


Mammalian nociceptors have been classified into subclasses based on differential neurotrophin sensitivity and binding of the plant isolectin B4 (IB4). Most of the nerve growth factor-responsive IB4-negative (IB4 (-)) nociceptors contain neuropeptides such as substance P and calcitonin gene-related peptide, whereas the glial-derived neurotrophic factor-responsive IB4-positive (IB4 (+)) neurons predominantly lack such neuropeptides. We hypothesized that the differences in neuropeptide content between IB4 (+) and (-) neurons might be reflected in differences in stimulated exocytosis and/or endocytosis. To address this, we monitored the secretory activity of acutely dissociated neurons from adult rat trigeminal ganglia (TRG) using cell membrane capacitance (Cm) measurements and the fluorescent membrane-uptake marker N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)pyridinium dibromide (FM4-64). Cm measurements were performed under whole-cell voltage clamp and neurons were depolarized from -75 mV to +10 mV to elicit exocytosis. Both types of TRG neurons showed similarly-sized, calcium-dependent increases in Cm, demonstrating that both IB4 (+) and (-) TRG neurons are capable of stimulated exocytosis. However, the...Continue Reading

Mentioned in this Paper

CALCA gene
Entire Trigeminal Ganglion
Biochemical Pathway
Calcitonin Gene-Related Peptide
Presynaptic Terminals
Calcium [EPC]
Deoxyribonuclease I
Tissue Membrane
CALCA wt Allele
SLC25A29 gene

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