Bubble pressure measurement of micropipet tip outer diameter

Mittman, Scott; Flaming, Dale G.; Copenhagen, David R.; Belgum, Jack H.

doi:10.1016/0165-0270(87)90010-0

Cited by 73 publications

(37 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Patch pipettes were fabricated from Jencons borosilicate glass (catalog number M15/10; Jencons Limited, Bedfordshire, UK), fire-polished to approximately 1·m (bubble number 5.0) (Mittman et al, 1987) and coated near the tip with beeswax to reduce the pipette capacitance. Pipette resistances were between 7 and 10·M⍀, which produced high-resistance seals (between 8 and 14·G⍀) by applying gentle suction to the lumen of the pipette upon contact with the cell.…”

Section: Methodsmentioning

confidence: 99%

Vomeronasal sensory neurons fromSternotherus odoratus(stinkpot/musk turtle) respond to chemosignalsviathe phospholipase C system

Brann

Fadool

2006

Journal of Experimental Biology

View full text Add to dashboard Cite

SUMMARY The mammalian signal transduction apparatus utilized by vomeronasal sensory neurons (VSNs) in the vomeronasal organ (VNO) has been richly explored, while that of reptiles, and in particular, the stinkpot or musk turtle Sternotherus odoratus, is less understood. Given that the turtle's well-known reproductive and mating behaviors are governed by chemical communication, 247 patch-clamp recordings were made from male and female S. odoratus VSNs to study the chemosignal-activated properties as well as the second-messenger system underlying the receptor potential. Of the total neurons tested, 88 (35%) were responsive to at least one of five complex natural chemicals, some of which demonstrated a degree of sexual dimorphism in response selectivity. Most notably, male VSNs responded to male urine with solely outward currents. Ruthenium Red, an IP3 receptor(IP3R) antagonist, failed to block chemosignal-activated currents,while the phospholipase C (PLC) inhibitor, U73122, abolished the chemosignal-activated current within 2 min, implicating the PLC system in the generation of a receptor potential in the VNO of musk turtles. Dialysis of several second messengers or their analogues failed to elicit currents in the whole-cell patch-clamp configuration, negating a direct gating of the transduction channel by cyclic adenosine monophosphate (cAMP), inositol 1,4,5-trisphosphate (IP3), arachidonic acid (AA), or diacylglycerol(DAG). Reversal potential analysis of chemosignal-evoked currents demonstrated that inward currents reversed at –5.7±7.8 mV (mean ±s.e.m.; N=10), while outward currents reversed at–28.2±2.4 mV (N=30). Measurements of conductance changes associated with outward currents indicated that the outward current represents a reduction of a steady state inward current by the closure of an ion channel when the VSN is exposed to a chemical stimulus such as male urine. Chemosignal-activated currents were significantly reduced when a peptide mimicking a domain on canonical transient receptor potential 2 (TRPC2), to which type 3 IP3 receptor (IP3R3) binds, was included in the recording pipette. Collectively these data suggest that there are multiple transduction cascades operational in the VSNs of S. odoratus, one of which may be mediated by a non-selective cation conductance that is not gated by IP3 but may be modulated by the interaction of its receptor with the TRPC2 channel.

show abstract

Section: Methodsmentioning

confidence: 99%

Vomeronasal sensory neurons fromSternotherus odoratus(stinkpot/musk turtle) respond to chemosignalsviathe phospholipase C system

Brann

Fadool

2006

Journal of Experimental Biology

View full text Add to dashboard Cite

show abstract

“…Whole-cell current-or voltage-clamp recordings were achieved by forming gigaohm seals on the soma of olfactory receptor cells with borosilicate glass patch electrodes (Boralex, Dynalabs) with tip diameters of approximately 1 pm (bubble number, ca. 5; Mittman et al, 1987). The electrodes were coated with Sylgard to reduce stray capacitance in most, but not all, recordings.…”

Section: Methodsmentioning

confidence: 99%

Cyclic nucleotides mediate an odor-evoked potassium conductance in lobster olfactory receptor cells

Michel

Ache

1992

J. Neurosci.

View full text Add to dashboard Cite

Odors activate at least two distinct transduction pathways in lobster olfactory receptor cells that, respectively, excite and inhibit the cell. Data presented suggest that odors selectively activate the inhibitory conductance through the second messenger cAMP. Not all cells support both odor-evoked excitatory and inhibitory conductances; in the current investigation, about 50% of the cells tested were inhibited by odors. In the majority of cells that, as a group, support an inhibitory response to odor stimulation, activation of adenylate cyclase with forskolin or inhibition of phosphodiesterase activity with 3-isobutyl-1- methylxanthine (IBMX) elicits an outward current with a time course similar to that of odor-evoked outward currents. The membrane-permeant cyclic nucleotide analogs 8-Br-cAMP and 8-Br-cGMP have a similar effect. Forskolin and IBMX enhance the magnitude of odor-evoked outward currents when the drug and the odor are copresented to the cell. In contrast, these same drugs have little or no effect on cells that, as a group, fail to support an inhibitory response to odor stimulation. This study provides the first direct evidence implicating cAMP in olfactory transduction in an invertebrate and contrasts with similar studies in vertebrates that have implicated cAMP as a second messenger mediating excitation.

show abstract

“…Voltage-clamp and single-channel recording were performed by conventional patch-clamp methods with commercially available electronics. Gigaohm seals were formed with unpolished borosilicate glass pipettes (Boralex or Jencons) pulled to tip diameters of -1 1Lm (bubble numbers, 4.6-5.2) (19). Sylgard 184 (Dow Coming) was applied to the pipette neck to reduce capacitance.…”

Section: Methodsmentioning

confidence: 99%

Histamine directly gates a chloride channel in lobster olfactory receptor neurons.

McClintock

Ache

1989

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Biogenic amines mediate many types of intercellular communication in multicellular organisms. Heretofore, little direct evidence has indicated that biogenic amines produce intracellular responses other than by triggering the enzymatic production of second messengers. Our electrophysiological studies of lobster olfactory receptor neurons now reveal that one biogenic amine, histamine, can directly gate an ion channel. The channel responds to histamine concentrations of 1 ,xM or more, is permeable primarily to Cl-, is more active at depolarized potentials, and has a conductance of 44 pS in the American lobster and 66 pS in the Caribbean spiny lobster. The expression of this ligand-gated channel in olfactory receptor neurons implies that these neurons are targets of a regulatory or feedback process.Histamine (HA) is a putative neurotransmitter and important neuroregulatory compound in diverse species (1-4). The intracellular effector mechanisms mediating HA responses investigated to date involve biochemical second messengers (5-9). We recently discovered that application of HA to the somata of spiny lobster olfactory receptor neurons suppresses both spontaneous and odor-evoking spiking in these cells by rapidly activating a Cl-current (10). The rapid time course of this effect, as well as recent evidence that HA mediates fast synaptic transmission in arthropods (11-15) and molluscs (1, 16), raises the possibility that HA can also act by directly gating ion channels. We now provide evidence that lobster olfactory receptor neurons express a chloride channel that is directly gated by HA. Evidence is also provided to support the conclusion that this channel mediates the suppressive action of HA on lobster olfactory receptor neurons. MATERIALS AND METHODSAnimals. Adult specimens of the Caribbean spiny lobster Panulirus argus were collected in the Florida Keys and maintained in flowing seawater at 18°C-23°C. Similar specimens of the American lobster Homarus americanus were purchased from commercial suppliers in Woods Hole, MA, and were maintained in flowing seawater at 13°C-17°C.Patch-Clamp Recording. Olfactory receptor neurons were prepared for patch-clamp recording as described (17, 18). Briefly, olfactory organs were cut into hemicylindrical sections, exposing the clusters of receptor neuron somata. Sections from American lobsters were treated with collagenase (1 mg/ml; Sigma, type 1A) for 60 min followed by trypsin(1 mg/ml in Ca2+-free saline; Sigma, type IX) for another 20 min. Sections from spiny lobsters were treated with Lcysteine-activated papain (0.25 mg/ml; Sigma, type IV) for 20 min and then with trypsin for another 20 min. For whole-cell voltage-clamp recording, somata were isolated by drawing clusters of somata into a fire-polished glass pipette and expelling them into a recording dish, a process that severed the dendrite and any remaining axon from these bipolar neurons. Voltage-clamp and single-channel recording were performed by conventional patch-clamp methods with commercially available electron...

show abstract

Bubble pressure measurement of micropipet tip outer diameter

Cited by 73 publications

References 4 publications

Vomeronasal sensory neurons fromSternotherus odoratus(stinkpot/musk turtle) respond to chemosignalsviathe phospholipase C system

Vomeronasal sensory neurons fromSternotherus odoratus(stinkpot/musk turtle) respond to chemosignalsviathe phospholipase C system

Cyclic nucleotides mediate an odor-evoked potassium conductance in lobster olfactory receptor cells

Histamine directly gates a chloride channel in lobster olfactory receptor neurons.

Contact Info

Product

Resources

About