| First Author | Mauban JR | Year | 2014 |
| Journal | Am J Physiol Heart Circ Physiol | Volume | 307 |
| Issue | 2 | Pages | H173-81 |
| PubMed ID | 24858846 | Mgi Jnum | J:214301 |
| Mgi Id | MGI:5588743 | Doi | 10.1152/ajpheart.00182.2014 |
| Citation | Mauban JR, et al. (2014) A method for noninvasive longitudinal measurements of [Ca2+] in arterioles of hypertensive optical biosensor mice. Am J Physiol Heart Circ Physiol 307(2):H173-81 |
| abstractText | We used two-photon (2-p) Forster resonance energy transfer (FRET) microscopy to provide serial, noninvasive measurements of [Ca(2+)] in arterioles of living "biosensor" mice. These express a genetically encoded Ca(2+) indicator (GECI), either FRET-based exMLCK or intensity-based GCaMP2. The FRET ratios, Rmin and Rmax, required for in vivo Ca(2+) calibration of exMLCK were obtained in isolated arteries. For in vivo experiments, mice were anesthetized (1.5% isoflurane), and arterioles within a depilated ear were visualized through the intact skin (i.e., noninvasively), by 2-p excitation of exMLCK (at 820 nm) or GCaMP2 (at 920 nm). Spontaneous or agonist-evoked [Ca(2+)] transients in arteriolar smooth muscle cells were imaged (at 2 Hz) with both exMLCK and GCaMP2. To examine changes in arteriolar [Ca(2+)] that might accompany hypertension, five exMLCK mice were implanted with telemetric blood pressure transducers and osmotic minipumps containing ANG II (350 ng.kg(-1).min(-1)) and fed a high (6%)-salt diet for 9 days. [Ca(2+)] was measured every other day in five smooth muscle cells of two to three arterioles in each animal. Prior to ANG II/salt, [Ca(2+)] was 246 +/- 42 nM. [Ca(2+)] increased transiently to 599 nM on day 2 after beginning ANG II/salt, then remained elevated at 331 +/- 42 nM for 4 more days, before returning to 265 +/- 47 nM 6 days after removal of ANG II/salt. In summary, two-photon excitation of exMLCK and GCaMP2 provides a method for noninvasive, longitudinal quantification of [Ca(2+)] dynamics and vascular structure in individual arterioles of a particular animal over an extended period of time, a capability that should enhance future studies of hypertension and vascular function. |
