Abstract:

Force generation of red drum fish ventricular muscle were measured by attaching ventricular strips to a force transducer. Ventricular force measurements are investigated in non-oil exposed and oil exposed animals during five graded hypoxia steps from 7.0 to 1.5 mg L-1 O2. Following graded hypoxia, a force-frequency relationship was determined in 0.2 hertz Hz increments beginning at 0.2 hertz and ending with 1.6 hertz during normoxic conditions. The force transducer was connected to a Powerlab data acquisition hardware connected to a Macintosh running Labchart v8.1.4 data acquisition software. All Labchart files are converted to .txt files. Water quality spreadsheets have been converted to .csv files.

Suggested Citation:

Nelson, Derek and Dane Crossley. 2020. Myocardial force generation following crude oil in juvenile red drum fish (Sciaenops ocellatus). Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/JFXM72SD

Purpose:

To quantify generated force, rate of contraction, rate of 50% relaxation, during stepwise hypoxia in resting juvenile red drum fish following 24-hour exposure to 10% high-energy water accommodated fraction (HEWAF) of oil from surface. A force frequency relationship was is investigated following stepwise hypoxia.

Data Parameters and Units:

Tank ID Dilution or Stock Code; Date (DD-MMM-YY); Time (HH:MM); Period, Water Temperature (temp, deg. C); pH, dissolve oxygen (D.O., mg/L); salinity (ppt); total ammonia (uM); notes; recorded by; oil type; oil loading rate (g/L); Temperature (Temp, dec. C); Cross-sectional area (mm^2); Force (mN mm^-2); Rate of contraction (mN mm^-2 sec^-1); Rate of 50% relaxation (mN mm^-1 sec^-1), Frequency (Hz); PAH (ug/L); WAF preparation method (HEWAF = high-energy water accommodated fraction); Oil type (OFS = oil from the surface); Water/diluent volume (L); Mass of dispersant added (mg); Mass of oil added (mg); Calculated nominal concentration (mg/L); Time (HH:MM)

Methods:

The hearts of red drum fish are excised, transferred to oxygenated Ringer’s solution and cut into strips. One end of the strip is tied to surgical silk with a loop while the other end is secured to a clamp. The silk end is placed around a glass rod while the clamp side is connected to a force transducer. The strip is then submerged into a well containing Ringer’s solution and is stimulated by platinum electrodes at a stimulus voltage and a stimulation frequency at 1 hertz, similar to the measured resting heart rate of red drum. A micrometer screw is used to stretch the strip to obtain maximum force. A stepwise hypoxia challenge is exerted by bubbling nitrogen gas into the bath wells allowing the investigation of oxygen availability to maximum force. A force-frequency relationship is obtained following the hypoxia challenge by lowering the stimulation frequency from 1.6 hertz to 0.2 hertz in 0.2 increments.

Instruments:

Powerlab data acquisition hardware; Labchart v8.1.4 data acquisition software

Individual Files: