Visualizing the Beating Heart in Drosophila

Summary

Technique required for visualizing the beating heart in larval and adult Drosophila are presented. Each life stage requires a different methodology.

Abstract

The Drosophila heart has recently emerged as a good model system for examining the genetic, cellular, and molecular mechanisms underlying function in myogenic hearts. A key step in examining heart function in the fly is finding a way to access the heart in a manner that preserves its myogenic function while still allowing the beating heart organ to be observed and recorded. Two different methods for observing and recording the beating heart in both larva and adult Drosophila are described here. Our semi-intact preparation using adult flies allows clear visualization of the abdominal heart without interference from the pigmented cuticle and overlying fat bodies. To record larval heart beats it is necessary to immobilize the larva, which minimizes body wall movements thereby reducing heart movements that are not associated with myocardial contractions. Our methodologies produce stable adult and larval heart preparations that can beat for hours at rates of 1-3 Hz.

Protocol

Before you start

Adult hearts

1. Freshly prepare artificial hemolymph (AH) solution containing 108mM Na⁺, 5mM K+, 2mM Ca²⁺, 8mM MgCl₂, 1mM NaH₂PO₄, 4mM NaHCO₃, 10mM sucrose, 5mM trehalose, 5mM HEPES (pH 7.1, all reagents from Sigma Chemicals). The sucrose and trehalose should be added to the AH from refrigerated stock solutions just prior to use in order to prevent bacterial contamination.
2. Bring AH to room temperature and oxygenate the solution by air-bubbling for at least 15 min.
3. Pull several fine capillaries (e.g. Glass Capillaries, 100ul....

Discussion

The Drosophila model has proven to be a powerful genetic tool that has been used to address a variety of scientific questions ranging from embryological development to learning and memory. Recently this versatile model organism has been used to investigate the genetics of heart function in the fly. A number of attempts to quantify heart physiology in adult Drosophila have relied on observations made in intact flies through the abdominal cuticle. Most of these approaches have relied on visual observation or recordings of .......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Micro Dissecting Spring Scissors (curved)	Roboz Surgical Instruments Co.	RS-5611	Good for gross cuts (Step 3)
Micro Dissecting Spring Scissors (straight)	Roboz Surgical Instruments Co.	RS-5620
Dumont #55 forceps	Fine Science Tools	11295-51
Dumont #5 forceps	Fine Science Tools	11295-10
Glass Capillaries, 100ul	VWR international	53432-921
Glass Capillaries, fine	Science Products	GB100T8P
Pipette Puller	Sutter Equipment	P-97	Both horizontal and vertical pipette pullers will work
Plastic tubing	Tygon	1/16” inner diameter	for 100μl capillaries
Plastic tubing	Tygon	1/32” inner diameter	for small capillaries
Histoacryl® tissue adhesive	B. Braun Medical