<em>Drosophila melanogaster</em> for Physiological Studies

Abstract

We present various methods to record cardiac function in the larval Drosophila. The approaches allow heart rate to be measured in unrestrained and restrained whole larvae. For direct control of the environment around the heart another approach utilizes the dissected larvae and removal of the internal organs in order to bathe the heart in desired compounds. The exposed heart also allows membrane potentials to be monitored which can give insight of the ionic currents generated by the myocytes and for electrical conduction along the heart tube. These approaches have various advantages and disadvantages for future experiments that are discussed. The larval heart preparation provides an additional model besides the Drosophila skeletal NMJ to investigate the role of intracellular calcium regulation on cellular function. Learning more about the underlying ionic currents that shape the action potentials in myocytes in various species, one can hope to get a handle on the known ionic dysfunctions associated to specific genes responsible for various diseases in mammals.

Pharmacological identification of cholinergic receptor subtypes on Drosophila melanogaster larval heart

“…The Drosophila heart is very sensitive to pH (Gu and Singh 1995); therefore, the saline is adjusted to pH 7.1 and maintained with the high concentration of buffer as described in de Castro et al (2014). The larval dissection is described in detail by Gu and Singh (1995) and in video by Cooper et al (2009). An illustration of the preparation used can be found in Desai-Shah et al (2010).…”

“…After collection, early third instar larvae were pinned ventral side up on a glass plate and dissected in a droplet of saline (Cooper et al 2009). The Drosophila heart is very sensitive to pH (Gu and Singh 1995); therefore, the saline is adjusted to pH 7.1 and maintained with the high concentration of buffer as described in de Castro et al (2014).…”

“…Hemolymph is drawn into the heart through ostia in the posterior pump and circulated through an aorta back into the visceral lumen (Molina and Cripps 2001). The pacemaker of the larval heart is located caudally and, like in the human heart, is myogenic (Dowse et al 1995;Gu and Singh 1995;Johnson et al 1998Johnson et al , 2001Rizki 1978) meaning action potentials in this tissue are initiated in the absence of neural innervation within the cardiac muscle itself (Cooper et al 2009;Desai-Shah et al 2010). In the late 3rd instar there appear to be neurons innervating the rostral tissue of the aorta, but the function of this innervation has not been addressed (Johnstone and Cooper 2006).…”

Human Disease Models inDrosophila melanogasterand the Role of the Fly in Therapeutic Drug Discovery

“…Significantly, the beating fly heart can be observed through a traditional dissection microscope for analysis. An excellent resource for protocols on visualization, dissection, and electrophysiological recording from larva heart is a publication from Robin Cooper and the accompanying video tutorial (Cooper et al, 2009). Using these methods, it is possible to easily examine the effects of pharmacological agents on heart function (Dasari and Cooper, 2006;Dasari et al, 2007;Neckameyer et al, 2007).…”

3D chromatin interactions organize Yan chromatin occupancy and repression at the even-skipped locus

“…The number of heartbeats of white prepupae in a 15-sec period was determined as described in Cooper et al 2009) and charted as hertz (cycles per second).…”