Surgical procedures are the same as last week. Read over the lab manual to refresh your memory. You will need to be able to identify surgical anesthesia in your rat (one rat per group this week). Cannulate the bladder (do not forget to fill the cannula with mammalian saline or you will ruin the experiment). Balance the drop counter transducer and test it by dropping water from a syringe onto the sensing disc. Increase the sensitivity if the drops are not recorded. You will need to get set up and start recording your 20-minute Control record before hearing the pre-lab lecture.
Part A: Control Record for Urine Production
Recording Criteria:
Title: Control Record for Urine Production
Transducer: Drop Counter
Paper Speed: 0.025 cm/sec
Timer: 60 sec.
Label all drops and artifacts on record.
For part A make a graph of Time in minutes vs. Cumulative drops
Discuss the three phases of urine formation (filtration, selective reabsorption, and secretion) in detail. (Ex.) What is filtered? What isn't filtered? What drives filtration? How do ADH and aldosterone effect reabsorption? Etc.
Part B: Effect of Saline on Urine Production
Now cannulate the iliac for drug administration. If you miss the first time, have a TA cannulate the other leg. Once you are ready turn the record on and inject 5 ml of 0.9% saline (inject slowly!) and mark with the event button on the Physiograph machine. Record for 20 minutes. Note the change in rate from the control record.Recording Criteria:
Title: Effect of Saline on Urine Production
Transducer: Drop Counter
Paper Speed: 0.025 cm/sec
Timer: 60 sec.
Drug Administered: 0.9 % saline
Drug Dosage: 5 ml
Label all drops and artifacts on record.
For part B make a graph of Time in minutes vs. Cumulative drops for the control and for the saline record (Make sure you get the data from the Part A record). Plot Time in minutes vs. cumulative drops for both records on the same graph (two lines).
Discussion: What happens to Blood Pressure when you inject this volume of fluid? What happens to GFR? What happens to PCOP after injection? How does this effect GFR?
Part C: Effect of Glucose on Urine Production
Inject 3 cc of glucose solution. Remember to hit the event marker when you inject. Make sure you inject slowly. Record 10 minutes after injection.Recording Criteria:
Title: Effect of Glucose on Urine Production
Transducer: Drop Counter
Paper Speed: 0.025 cm/sec
Timer: 60 sec.
Drug Administered: 10% glucose
Drug Dosage: 3 ml
Label all drops and artifacts on record.
For Part C make a graph comparing the Control record data to the Glucose data. Plot Time in minutes vs. cumulative drops for both records on the same graph (two lines).
Discuss effects on osmotic pressure and Tmax and resulting change in urine production.
Part D: Effect of Lasix on Urine Production
Inject 3 cc of Lasix. Record for 5 minutes. Inject .1cc of epinephrine and record for 5 more minutes.ReturnRecording Criteria:
Title: Effect of Lasix on Urine Production
Transducer: Drop Counter
Paper Speed: 0.025 cm/sec
Timer: 60 sec.
Drug Administered: Lasix (1mg/ml), Epinepherine (.01 mg/ml)
Drug Dosage: 3 ml, 0.1 ml
Label all drops and artifacts on record.
For Part D make a graph comparing the Control record data to the Lasix followed by Epi data. Plot Time in minutes vs. cumulative drops for both sets of data on the same graph (two lines).
Discuss the effects of Lasix and Epinepherine on urine production. What is a loop diuretic? Where are the adrenergic receptors that cause the response you observed in urine production? What type and ratio are the receptors?