1. Intracellular recording techniques were used to study neurotransmitter release mechanisms in postganglionic sympathetic nerve terminals of the rat isolated anococcygeus muscle. 2. Low concentrations of the N-type calcium channel blocker omega-conotoxin GVIA (omega-CgTX GVIA) irreversibly abolished excitatory junction potentials (EJPs) evoked by trains of < or = five stimuli at 10 Hz. When the frequency of stimulation was increased (10-50 Hz) trains of stimuli evoked EJPs even in the presence of 1 microM omega-CgTX GVIA. We have termed this omega-CgTX GVIA-resistant release 'residual release'. EJP amplitude in the presence of omega-CgTX GVIA depended on both the frequency and number of stimuli in a train. 3. Residual release was inhibited by the P-type calcium channel blocker omega-agatoxin IVA (100 nM). However, even in the presence of both toxins, longer trains of stimuli could still evoke neurotransmitter release. 4. Residual release was abolished by omega-conotoxin MVIIC and by the non-specific calcium channel antagonist omega-grammotoxin SIA. Therefore, it would appear that a heterogeneous population of calcium channels is involved in mediating neurotransmitter release from these sympathetic nerve terminals.
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http://dx.doi.org/10.1113/jphysiol.1997.sp021931 | DOI Listing |
Background: The locus coeruleus (LC), is the first brain region to develop hyperphosphorylated tau (ptau) inclusions in Alzheimer's disease (AD) and undergoes catastrophic degeneration in later stages of the disease. Importantly, the LC is the main noradrenergic nucleus in the brain and source of NE in the forebrain, and dysregulation of the neurotransmitter norepinephrine (NE) is associated with AD symptoms, as its release in the forebrain regulates attention, arousal, stress response, and learning and memory. Moreover, the LC may transmit pathogenic tau to the forebrain via its extensive projections.
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January 2025
Department of Pathology, University of Iowa Health Care, Iowa City, IA, United States.
Background: Heparin-induced thrombocytopenia (HIT) is a potentially life-threatening adverse drug reaction with numerous diagnostic challenges. Diagnosis of HIT begins with 4T score clinical assessment, followed by laboratory testing for those not deemed low risk. Laboratory testing for HIT includes screening [enzyme-linked immunosorbent assay (ELISA)] and confirmatory [serotonin release assay (SRA)] assays, wherein SRA testing can be pursued following a positive ELISA result.
View Article and Find Full Text PDFNat Commun
January 2025
Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, Jiangsu, China.
Norepinephrine (NE) released from locus coeruleus (LC) noradrenergic (NAergic) neurons plays a pivotal role in the regulation of olfactory behaviors. However, the precise circuits and receptor mechanisms underlying this function are not well understood. Here, in DBH-Cre mice model, we show that LC NAergic neurons project directly to both anterior piriform cortex (aPC) and the olfactory bulb (OB).
View Article and Find Full Text PDFNat Commun
January 2025
Department of Pharmacology and Therapeutics, Florida Chemical Senses Institute, Center for Addiction Research and Education; University of Florida College of Medicine, Gainesville, FL, USA.
Sniffing is a motivated behavior displayed by nearly all terrestrial vertebrates. While sniffing is associated with acquiring and processing odors, sniffing is also intertwined with affective and motivated states. The systems which influence the display of sniffing are unclear.
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