Experimental effects of drugs of the efferent nervous system on blood pressure in rabbits

Summary

Learning the method of acute blood pressure experiment in anesthetized animals; observing the effect of efferent nerve drugs on the blood pressure of animals, deepening the understanding of the interaction relationship of these drugs, and analyzing the mechanism of action initially according to the receptor theory. This experiment utilizes the method of direct measurement of blood pressure, the arterial cannula inserted into the common carotid artery and the pressure transducer constitute an anticoagulant closed system, and the blood pressure value can be read out from the BL-420 system connected with the pressure transducer.

Operation method

direct blood pressure (DBP) measurement

Principle

Using a direct blood pressure measurement method, an arterial cannula inserted into the common carotid artery and a pressure transducer form an anticoagulant closed system, and the blood pressure value can be read from the BL-420 system connected to the pressure transducer.

Materials and Instruments

Rabbit
Sodium pentobarbital Heparin Saline Adrenaline hydrochloride Norepinephrine bitartrate Isoproterenol Phentolamine injection
Scalpel Surgical scissors Civilian scissors Hemostatic forceps Tracheal intubation Arterial intubation Arterial clips Scalp intravenous needles Pressure transducer Computer Recording device Syringe Iron stent Spiral clamps Cotton wool Medicinal cotton Gauze

Move

I. Steps

⒈ Take a rabbit, weigh, intraperitoneal injection of sodium pentobarbital 30 mg/kg (i.e., 3% sodium pentobarbital solution 1 ml/kg), anesthesia, the animal dorsal position fixed on the operating table.
　　　Find the vein at the ear margin, insert a scalp intravenous needle attached to the syringe, and push saline slowly and continuously without interruption.
Ͻ Clip the neck hair and incise the neck skin centrally to separate the trachea. Thread a line under the trachea, gently lift the trachea, make an inverted "T" shaped incision, insert the tracheal tube, and secure it with a ligature.
Singing: Separate the common carotid artery from the carotid sheath on the side of the trachea (note the presence of the vagus nerve, which should be separated from the common carotid artery), thread a wire underneath the common carotid artery proximally and distally, and ligate the distal end; then clip the proximal end of the artery with arterial clips, and make a "V" shaped incision with an ophthalmologic scissors close to the ligature, and insert the tube filled with The arterial cannula with sodium citrate solution or heparin solution was inserted in a cardiac direction, ligated and fixed to the arterial cannula. The arterial cannula is connected to the pressure transducer and connected to the 410-BioSignal Acquisition System; slowly release the common carotid artery clip and trace the normotensive curve.
Carefully turn on the computer and click on the BL-420 icon on the desktop to enter the blood pressure experiment system. Trace the normal blood pressure curve, and then inject the following drugs into the vein from the ear margin in sequence. Observe the changes in blood pressure caused by the administration of the drugs. After the blood pressure returns to its original level or stabilizes, the next drug is administered. Immediately after each administration, push in 2 ml of saline to flush the remaining drug into the vein.
Observation of drug administration

Inject the following drugs sequentially from the vein, observe the changes in blood pressure, and think about the principles of the changes.
1. Observe the effect of adrenomimetic drugs:
(1) Epinephrine hydrochloride 0.1 mg/kg
(2) norepinephrine bitartrate 0.1 mg/kg
(3) Isoproterenol 0.05 mg/kg
2. Observe the effect of the application of the alpha-blocker phentolamine on the action of the adrenomimetic drugs:
(1) Phentolamine 0.1 mg/kg was injected slowly and the following drugs were administered 2-3 minutes after the application:
(2) Epinephrine hydrochloride 0.1 mg/kg
(3) norepinephrine bitartrate 0.1 mg/kg
(4) Isoprenaline 0.05 mg/kg
3. Observe the effect of the β-blocker cardioplegia on the effects of adrenomimetic drugs:
(1) 1 % Cardioplegia 0.1 mg/kg was injected slowly and the following drugs were administered 5-10 minutes after the application:
(2) Epinephrine hydrochloride 0.1 mg/kg
(3) norepinephrine bitartrate 0.1 mg/kg
(4) Isoprenaline 0.05 mg/kg
Results

Caveat

⒈ This experiment was carried out with rabbits, because of the poor tolerance of rabbits, some results may not be very typical.⒈ The dose in the experiment is calculated according to the general situation, if necessary, according to the specific circumstances of the appropriate increase or decrease.⒊ 为避免形成血栓，所建静脉通道在不给药时应连续、缓慢地推注生理盐水。

Common Problems

I. What is the effect of each of the adrenomimetics and the antiadrenomimetics on blood pressure? How do they interact with each other? Why?

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