The origin of the skewed amplitude distribution of spontaneous excitatory junction potentials in poorly coupled smooth muscle cells
| Autor: | Keith L. Brain, T.C. Cunnane, John S. Young |
|---|---|
| Jazyk: | angličtina |
| Předmět: |
Male
Time Factors sEJP spontaneous excitatory junction potential SMC smooth muscle cell Spider Venoms LTX α-latrotoxin confocal microscopy Membrane Potentials BAPTA-1 AM 1 2-bis(o-aminophenoxy)ethane-N N N′ N′-tetraacetic acid–1 acetoxymethyl ester smooth muscle Mice 0302 clinical medicine Adenosine Triphosphate Vas Deferens Electric Impedance EJP excitatory junction potential neurotransmission Membrane potential 0303 health sciences Mice Inbred BALB C Microscopy Confocal General Neuroscience Purinergic receptor Vas deferens calcium imaging medicine.anatomical_structure Amplitude cardiovascular system Excitatory postsynaptic potential NF449 4 4′ 4″ 4‴-[carbonylbis[imino-5 1 3-benzenetriyl bis(carbonyl-imino)]]tetrakis(benzene-1 3-disulfonic acid) medicine.medical_specialty α-SNAP α–soluble N-ethylmaleimide-sensitive factor attachment protein Neuroeffector Neuroscience(all) Myocytes Smooth Muscle sEJP Dose-Response Relationship Immunologic Neuromuscular Junction Neurotransmission Biology In Vitro Techniques Neuromuscular junction 03 medical and health sciences Internal medicine medicine Animals Calcium Signaling 030304 developmental biology PSS physiological salt solution NCT neuroeffector calcium transient Electric Stimulation ATP Endocrinology Cellular Neuroscience Biophysics 030217 neurology & neurosurgery |
| Zdroj: | Neuroscience |
| ISSN: | 0306-4522 |
| DOI: | 10.1016/j.neuroscience.2006.11.054 |
| Popis: | The skewed amplitude distribution of spontaneous excitatory junction potentials (sEJPs) in the mouse vas deferens and other electrically-coupled smooth muscle syncytia has been attributed to electrically-attenuated depolarizations resulting from the spontaneous release of quantized packets of ATP acting on remote smooth muscle cells (SMCs). However, in the present investigation surface SMCs of the mouse isolated vas deferens were poorly electrically coupled, with input resistances (176+/-18 MOmega, range: 141-221 MOmega, n=4) similar to those of dissociated cells. Furthermore, the amplitude of evoked EJPs was more variable in surface compared with deeper SMCs (F test, F=17.4, P0.0001). Using simultaneous electrophysiology and confocal microscopy to investigate these poorly-coupled cells, it is shown that alpha-latrotoxin-stimulated sEJPs correlate, in timing (median delay ranged from -30 to -57 ms, P0.05 in all experiments, n=5) and amplitude (Pearson product moment correlation, rho0.55 and P0.001), with purinergic neuroeffector Ca2+ transients (NCTs) in SMCs. The temporal correlation between sEJPs of widely ranging amplitude with NCTs in the impaled SMC demonstrates that all sEJPs could arise from neurotransmitter action on the impaled cell and that the skewed distribution of sEJPs can be explained by the variable effect of packets of ATP on a single SMC. The amplitude correlation of sEJPs and NCTs argues against the attenuation of electrical signal amplitude along the length of a single SMC. The skewed sEJP amplitude distribution arising from neurotransmitter release on single SMCs is consistent with a broad neurotransmitter packet size distribution at sympathetic neuroeffector junctions. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|