Mechanosensitive currents in putative aortic baroreceptor neurons in vitro.
1. Whole cell patch-clamp experiments were conducted to determine whether rat aortic baroreceptor neurons contain mechano-sensitive conductances. 2. Putative aortic baroreceptor neurons in the nodose ganglia were identified by injecting DiI onto the adventitia of the aortic arch. Nodose ganglia neurons were dissociated after > or = 1 wk. A fluorescein-conjugated tetanus toxin fragment was used to confirm that the cells labeled with DiI in culture were neurons. 3. Hypoosmotic stretch significantly increased the conductance of DiI-labeled neurons (n = 19). The reversal potential of the response was -11 +/- 1 (SE) mV. 4. In experiments on unlabeled neurons, only 7 of 13 cells showed increases in conductance. BC3H1 cells, a mouse tumor cell line, showed no changes in conductance. 5. Gadolinium (20 microM), a putative blocker of mechanosensitive channels, prevented the increase in conductance produced by hypoosmolality in seven of seven labeled cells. Equimolar concentrations of lanthanum (n = 6) and omega-conotoxin GVIA (1 microM, n = 4), which block voltage-gated calcium channels, failed to significantly affect the inward current.
Cunningham
J T
JT
Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City 52242, USA.
Wachtel
R E
RE
Abboud
F M
FM
D000818:Animals; D001011:Aorta / Q000502:physiology*; D005071:Evoked Potentials; D066298:In Vitro Techniques; D009474:Neurons / Q000502:physiology*; D009620:Nodose Ganglion / Q000502:physiology; D009995:Osmosis; D018408:Patch-Clamp Techniques; D010812:Physical Stimulation; D011311:Pressoreceptors / Q000502:physiology*; D051381:Rats