scholarly journals Detection of activity-dependent vasopressin release from neuronal dendrites and axon terminals using sniffer cells

2018 ◽  
Vol 120 (3) ◽  
pp. 1386-1396 ◽  
Author(s):  
Cristian Zaelzer ◽  
Claire Gizowski ◽  
Christopher K. Salmon ◽  
Keith K. Murai ◽  
Charles W. Bourque
Keyword(s):  
Electrical Stimulation ◽  
Response Analysis ◽  
Living Tissue ◽  
Vasopressin Release ◽  
Human Embryonic Kidney Cells ◽  
Functional Roles ◽  
Axon Terminals ◽  
Neuronal Dendrites ◽  
Calcium Indicator ◽  
Stimulation Of

Our understanding of neuropeptide function within neural networks would be improved by methods allowing dynamic detection of peptide release in living tissue. We examined the usefulness of sniffer cells as biosensors to detect endogenous vasopressin (VP) release in rat hypothalamic slices and from isolated neurohypophyses. Human embryonic kidney cells were transfected to express the human V1a VP receptor (V1aR) and the genetically encoded calcium indicator GCaMP6m. The V1aR couples to Gq11, thus VP binding to this receptor causes an increase in intracellular [Ca2+] that can be detected by a rise in GCaMP6 fluorescence. Dose-response analysis showed that VP sniffer cells report ambient VP levels >10 pM (EC50 = 2.6 nM), and this effect could be inhibited by the V1aR antagonist SR 49059. When placed over a coverslip coated with sniffer cells, electrical stimulation of the neurohypophysis provoked a reversible, reproducible, and dose-dependent increase in VP release using as few as 60 pulses delivered at 3 Hz. Suspended sniffer cells gently plated over a slice adhered to the preparation and allowed visualization of VP release in discrete regions. Electrical stimulation of VP neurons in the suprachiasmatic nucleus caused significant local release as well as VP secretion in distant target sites. Finally, action potentials evoked in a single magnocellular neurosecretory cell in the supraoptic nucleus provoked significant VP release from the somatodendritic compartment of the neuron. These results indicate that sniffer cells can be used for the study of VP secretion from various compartments of neurons in living tissue. NEW & NOTEWORTHY The specific functional roles of neuropeptides in neuronal networks are poorly understood due to the absence of methods allowing their real-time detection in living tissue. Here, we show that cultured “sniffer cells” can be engineered to detect endogenous release of vasopressin as an increase in fluorescence.

scholarly journals Secretion-related uptake of horseradish peroxidase in neurohypophysial axons.

1976 ◽  
Vol 70 (2) ◽  
pp. 294-303 ◽  
Author(s):  
D T Theodosis ◽  
J Dreifuss ◽  
M C Harris ◽  
L Orci
Keyword(s):  
Plasma Membrane ◽  
Electrical Stimulation ◽  
Horseradish Peroxidase ◽  
Secretory Granule ◽  
Morphometric Analysis ◽  
Neurosecretory Granules ◽  
Neurohypophysial Hormones ◽  
Axon Terminals ◽  
Granule Membrane ◽  
Stimulation Of

During secretion of the neurohypophysial hormones, oxytocin and vasopressin, secretory granule membrane is added to the plasma membrane of the axon terminals. It is generally assumed that subsequent internalization of this additional membrane occurs by endocytosis. In order to study this process, we have traced the uptake of intravenously injected horseradish peroxidase by neurohypophysial axons in rats and golden hamsters. Peroxidase reaction product within the secretory axons was found mainly in vacuolar and C-shaped structures of a size comparable with or larger than the neurosecretory granules. Our observations suggest that these large horseradish peroxidase (HRP)-impregnated vacuoles arise directly by a form of macropinocytosis. Morphometric analysis indicated that this form of membrane retrieval increased significantly after the two types of stimuli used, reversible hemorrhage and electrical stimulation of the pituitary stalk. Microvesicular uptake of HRP was found to be comparatively less.

Temporal Patterns of Vasopressin Release Following Electrical Stimulation of the Amygdala and the Neuroendocrine Pathway in the Monkey

1977 ◽  
Vol 23 (2) ◽  
pp. 61-75 ◽  
Author(s):  
J.N. Hayward ◽  
K. Murgas ◽  
K. Pavasuthipaisit ◽  
F.R. Perez-Lopez ◽  
M.V. Sofroniew
Keyword(s):  
Electrical Stimulation ◽  
Temporal Patterns ◽  
Vasopressin Release ◽  
Stimulation Of

Nucleus Z: a somatosensory relay to motor thalamus

1993 ◽  
Vol 69 (5) ◽  
pp. 1607-1620 ◽  
Author(s):  
R. Mackel ◽  
E. Miyashita
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Small Region ◽  
Axon Terminals ◽  
Natural Stimulation ◽  
Dorsal Columns ◽  
Dorsolateral Funiculus ◽  
Spinocerebellar Tract ◽  
Motor Thalamus ◽  
Stimulation Of

1. It was the aim of this study to show that nucleus Z of the cat medulla acts as a relay between the spinal cord and the ventral lateral (VL) nucleus of the motor thalamus. For this purpose, extracellular recordings were made from neurons that were antidromically identified by stimulation in the rostral thalamus, particularly VL, and orthodromically activated by electrical stimulation of the spinal cord and/or natural stimulation of the hindlimb. The electrophysiological work was complemented by anatomic work. Here, wheat germ agglutinin-horseradish peroxidase (WGA-HRP) was injected into nucleus Z and the termination sites of bulbothalamic projections were anterogradely labeled. 2. A total of 120 neurons were antidromically identified as projecting to thalamus: 101 to VL and 19 outside VL. The recording sites in nucleus Z were marked by dye injection or by electrolytic lesion. They were confined to a small region (roughly 1 mm in diameter), 2.8-3.7 mm rostral to obex, 2.9-3.8 mm lateral from the midline, and from the surface of the medulla to a depth of 1 mm. The antidromic latencies ranged between 0.8 and 3.2 ms, with no difference in latencies associated with location of neurons in nucleus Z or thalamic projection sites. 3. Injection of WGA-HRP labeled fibers and axon terminals in the contralateral thalamus. Terminal labeling was densest in the lateral parts of the mid- and caudal region of the VL nucleus and, to a lesser extent, in the adjacent rostrodorsal part of the ventro-posterior lateral (VPL) nucleus. The sites of terminal labeling in VL corresponded with location of antidromic stimulation sites. 4. Orthodromic activation of nucleus Z neurons was tested in response to electrical stimulation of the ipsilateral dorsolateral funiculus (which includes the dorsal spinocerebellar tract) and/or the dorsal columns. All neurons responded to stimulation of the dorsolateral funiculus (45/45). The responsiveness of 44 neurons was tested to stimulation of the dorsal columns. Only 8 of 44 tested responded with a discharge. The orthodromic latencies of unitary discharges ranged from 1.1 to 4.4 ms to stimulation of the dorsolateral funiculus, and from 1.1 to 4.9 ms to stimulation of the dorsal columns. Most responses are likely to be monosynaptic. Differences in latencies were not associated with location of recording sites or thalamic projection sites of nucleus Z neurons. 5. The responsiveness of many neurons (n = 84) was tested to natural stimulation of the ipsilateral hindlimb (which provides the sensory input to nucleus Z).(ABSTRACT TRUNCATED AT 400 WORDS)

Projections to the hypothalamus from buffer nerves and nucleus tractus solitarius in the cat

1980 ◽  
Vol 239 (1) ◽  
pp. R130-R136 ◽  
Author(s):  
F. R. Calaresu ◽  
J. Ciriello
Keyword(s):  
Electrical Stimulation ◽  
Carotid Sinus ◽  
Nucleus Tractus Solitarius ◽  
Firing Frequency ◽  
Regulatory Mechanisms ◽  
Ipsilateral Side ◽  
Central Projections ◽  
Functional Roles ◽  
Supraoptic Nuclei ◽  
Stimulation Of

In 18 cats anesthetized with chloralose, electrical activity of spontaneously active hypothalamic units was monitored for changes in firing frequency during electrical stimulation of carotid sinus (CSN) and aortic depressor (ADN) nerves and the nucleus tractus solitarius (NTS). Stimulation of the CSN altered the activity of 55% (381/691) of the tested. These responsive units were widely distributed in the ipsi- and contralateral hypothalamus. Of the units tested during stimulation of the ADN only 6% (17/274) changed their firing frequency. Responsive units were located only on the ipsilateral side and primarily in the paraventricular and supraoptic nuclei, Electrical stimulation of the NTS altered the firing frequency of all 84 hypothalamic units previously identified by stimulation of the CSN. NTS stimulation elicited responses that had a significantly shorter latency and followed significantly higher frequencies of stimulation when compared to stimulation of the CSN. These results demonstrate that the two buffer nerves have distinctly different central projections to the hypothalamus and suggest different functional roles for the ADN and CSN in homeostatic regulatory mechanisms mediated by the hypothalamus.

Regional intercostal activity during coughing and vomiting in decerebrate cats

1992 ◽  
Vol 70 (8) ◽  
pp. 1195-1199 ◽  
Author(s):  
Steve Iscoe ◽  
Laurent Grélot
Keyword(s):  
Electrical Stimulation ◽  
Abdominal Muscles ◽  
Regional Variations ◽  
Functional Roles ◽  
Intercostal Muscles ◽  
Laryngeal Nerves ◽  
Discharge Patterns ◽  
Spontaneously Breathing ◽  
Decerebrate Cats ◽  
Stimulation Of

Regional variations in the discharge patterns of the internal and external intercostal muscles of the middle and caudad thorax were studied in decerebrate, spontaneously breathing cats during coughing and vomiting. Coughing, induced by electrical stimulation of the superior laryngeal nerves, consisted of increased and prolonged diaphragmatic activity followed by a burst of abdominal activity. Mid-thoracic external and internal intercostal muscles discharged synchronously with the diaphragm and abdominal muscles, respectively. Caudal external and internal intercostal muscles, however, discharged synchronously with the abdominal muscles. Vomiting, induced by stimulation of the lower thoracic vagi, consisted of a series of synchronous bursts of diaphragmatic and abdominal activity (retching) followed by a prolonged abdominal discharge after the cessation of diaphragmatic activity (expulsion). Caudal external and internal intercostals discharged in phase with diaphragmatic and abdominal activity but both mid-thoracic intercostal muscles discharged out of phase with these muscles. These results indicate major differences in the control and functional roles of intercostal muscles at different thoracic levels during these behaviours.Key words: diaphragm, abdominal muscles, intercostal muscles.

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