Regulation of Blood Pressure (Ex. 17)

Procedure:

Today there will be a T. A. at each lab group to assist with the surgical techniques. Your rabbit will have been anesthetized with urethane. Therefore, any students involved in surgery or cleanup must wear gloves. The surgical procedure includes isolating both vagal nerves, tracheotomy, iliac cannula, and carotid cannula for the blood pressure transducer. To balance and calibrate the RP-1500 Pressure Transducer use the instructions on page 138 of your lab manual.

Part A: Control EKG and Arterial Blood Pressure

Procedure: Turn the record on and allow to run one page. Measure heart rate in beats per minute on the EKG channel. Measure the systolic and diastolic pressure using the recording from the pressure transducer.

Recording Criteria:

Transducer: RP-1500 Pressure Transducer

Paper Speed: 0.5 cm/sec

Timer: 1 sec

Calibration: 4cm = 100 mm Hg

Part B: Effect of Ach and the Effect of Atropine followed by Ach (Ach reversal) on BP and Heart Rate

Procedure: Cannulate the iliac for drug administration. Record 1/2 page then inject 0.2 ml of Ach, then record the effects.

Recording criteria:

Transducer: RP-1500 Pressure Transducer

Paper Speed: 0.5 cm/sec

Timer: 1 sec

Stimulus: Chemical

Drug Administered: Acetylchloline (0.1 mg/ml)

Drug dosage: 0.2 ml

Calibration: 4cm = 100 mm Hg

For the second record for part B record 1/2 page then inject 1 to 3 mls of Atropine. Turn off the record and wait 4 minutes. Turn the record on and let run for 1/2 page, then inject 0.2 ml of Ach. Record the effects and allow to return to normal.

Recording criteria:

Transducer: RP-1500 Pressure Transducer

Paper Speed: 0.5 cm/sec

Timer: 1 sec

Stimulus: Chemical

Drug Administered: Atropine (2 mg/ml), Acetylchloline (0.1 mg/ml)

Drug dosage: ? ml, and 0.2 ml, respectively

Calibration: 4cm = 100 mm Hg

Part C: Effect of Epinepherine

Procedure: Record 1/2 page then inject 0.1 ml of Epinepherine, record the effect.

Transducer: RP-1500 Pressure Transducer

Paper Speed: 0.5 cm/sec

Timer: 1 sec

Stimulus: Chemical

Drug Administered: Epinepherine (1.0 mg/ml)

Drug dosage: 0.1 ml

Calibration: 4cm = 100 mm Hg

Part D: Carotid Sinus Reflex and Medullary Ischemic Reflex

Procedure: The carotid sinus reflex should be run right after Part A. Record 1/2 page then simultaneously cut off blood flow through the carotids. Record the results (should be immediate and short).

Second record procedure: Record 1/2 page, then remove the iliac cannula (be sure and mark this event with your time and event marker), after the cannula is removed, the rabbit will bleed. As the blood pressure drops dramatically, you should see the Medullary Ischemic Reflex. Continue recording results until the rabbit dies. Recording criteria: same as Part A.