Recording of Rat ECG, BP and heart rate

different methods for recording Rat ECG , BP and heart rate. it include both invasive and non invasive methods. techniques include Foot electrode apparatus , tail cuff plethysmography (noninvasive) etc

1. Recording of Rat ECG , BP and Heart Rate Shivanshu Bajaj M .Pharmacy (Pharmacology) SPER , Jamia Hamdard Delhi

2. Different methods for ECG , BP and Heart Rate Non-Invasive method Invasive method Foot electrode apparatus Statham pressure transducer 6 channel ECG- Needle Electrodes tail cuff plethysmography ( noninvasive ) intra-arterial catheters Implantable Radio Telemetry

3. A SIMPLE METHOD FOR RECORDING THE ELECTROCARDIOGRAM AND HEART RATE FROM CONSCIOUS ANIMALS ( Foot electrode method ) The small bioelectrical signals of the heart detected at the body surface of animals are usually relayed to the initial amplifier stage of the electrocardiograph by the use of plate , needle or clip electrodes. Foot electrode method has been used to obtain recordings from conscious mice, rats, cats and dogs.

4. Apparatus comprised four separate copper plate electrodes mounted in either cork or blockboard , each sealed with a waterproof mastic seal to prevent leakage. The animal was placed on the apparatus so that each foot was in contact with a separate plate electrode. The front feet and left hind foot were used for recording standard leads while the right hind foot was grounded. Contact was facilitated by the use of gauze pads damped with isotonic saline. The dimensions of the apparatus were varied to suit the different animals . Heart rate was measured by a Neilson instantaneous ratemeter (40-250 and 80-500 beats/min scales) triggered from the QRS complex of the e.c.g

5. Neilson instantaneous ratemeter

6. Hyperresponsivity of spontaneously hypertensive rat to indirect measurement of blood pressure

7. METHODS Chronic, indwelling, tail arterial catheters. A nimals were anesthetized with sodium pentobarbital (40-50 mg/kg ip ), an incision ( 1.5 cm ) was made on the ventral surface of the tail about 1cm from its origin. Polyethylene tubing filled with sodium heparin was inserted into the ventral tail artery for a distance of more than 1 cm. The tubing was fixed in the artery and sutured to the tailskin , reflected dorsally and anteriorly, and led subcutaneously through a 25-cm length of &gauge, hollow-needle tubing to emerge at the back of the neck. The catheter was anchored to an adhesive-tape collar around the neck and then threaded through a 20-cm length of a thin wire spring T he tail arterial catheter, with its spring guard, was passed through a hole in the metal top and a plasticsyringe (1 ml) was connected to the catheter with a 23- gauge hypodermic needle. The indwelling tail arterial catheter was flushed twice daily with 0.5 ml of saline and animals were studied at least 24 h after the insertion of the catheter.

8. Measurements of blood pressure The blood pressure of the rats was directly through the tail arterial catheter by using a Statham pressure transducer and recorded by a Grass Polygraph. The transducer was placed at the same level as the rat. Heart rate was measured using the fluctuations of the arterial blood pressure to trigger a tachometer.

9. ECG measurement non-invasive in unconscious rat Software used- LabScribe 6 channel ECG- Needle Electrodes

10. Tail cuff plethysmography ( noninvasive )

11. Measurement of invasive blood pressure in rats Blood pressure (BP) measurement is one of the basic procedures in biomedical research. MATERIALS AND METHODS adult Wistar rats/Sprague Dawley rats heparin, urethane/ketamine + xylazine /pentobarbital sodium an intravenous cannula, 1 ml tuberculin syringe, a bulldog clamp respiratory tubing (6′′ infant feeding tube/ pediatric Ryle's tube may be used )

12. The materials used for recording the rat blood pressure. (a) bulldog clamp; (b) 6″ infant feeding tube [part of it used as respiratory tubing] for tracheostomy; (c) PE tube [15–20 cm length] with a 26 G × 1/2″ needle for femoral vein cannulation ; (d) PE tube [15–20 cm length] with a 26 G × 1/2″ needle for carotid artery cannulation ; and (e) disposable clip-on BP domes

13. Steps Intravenous cannula Tracheostomy Cannulation of carotid artery Student physiograph Data acquisition system Cannulation of femoral vein. (a) experimental animal on the surgical platform; (b-e) a small incision (1–2 cm) is made in the epidermis of the right thigh, and the matrix of collagen fibers interlaced with elastic fibers of the dermis is cleaned and femoral vein is identified; (f–h) femoral vein is cannulated using a femoral vein cannula

14. Procedure for tracheostomy. (a and b) a small incision (1.5–2 cm) is made in the neck of the rat for tracheostomy and carotid artery cannulation ; (c) slit incision is made on platysma to identify the trachea; (d–f) trachea is identified and small incision made on the cartilage tissue; (g and h) tracheostomy is performed using a piece of pediatric Ryle's tube

15. Cannulation of carotid artery. (a) right side of the carotid artery is separated from vagus nerve; (b and c) cephalic end of the blood vessel is tied to avoid the bifurcation of blood pressure; (d) cardiac end of the blood vessel is clamped with a bulldog clamp for cannulation ; (e) small platform is placed in the canulation site; (f–i) carotid artery is cannulated and tied; (j, k) The support platform and bulldog clamp are removed and ensure there is no leakage in the cannulation site; and (l) the carotid cannula is connected to pressure transducer through disposable clip-on BP domes

16. Complete rat blood pressure experimental setup

17. Direct Blood Pressure Monitoring in Laboratory Rodents via Implantable Radio Telemetry The ability to monitor and record precise blood pressure fluctuations in research animals is vital to research for human hypertension . Direct measurement of blood pressure via implantable radio telemetry devices is the preferred method for automatic collection of chronic, continuous blood pressure data. Two surgical techniques are described for instrumenting the two most commonly used laboratory rodent species with radiotelemetry devices. The basic rat procedure involves advancing a blood pressure catheter into the abdominal aorta and placing a radio transmitting device in the peritoneal cavity. The mouse technique involves advancing a thin, flexible catheter from the left carotid artery into the aortic arch and placing the telemetry device under the skin along the animal’s flank. Both procedures yield a chronically instrumented model to provide accurate blood pressure data from an unrestrained animal in its home cage.

18. The rat blood pressure telemetry device is positioned in the peritoneal cavity with the pressure sensing catheter advanced upstream into the abdominal aorta . The catheter insertion site is sealed with tissue adhesive and the transmitter body is sutured into the abdominal wall closure . .With effective post-surgical analgesia , a typical outbred rat will return to its pre-implantation body weight in 2–3 days and will return to normal circadian behavior patterns in 5–7 days . PA-C10 transmitter is used.

19. References Cardiovascular Genomics Methods and Protocols Edited byKeith DiPetrillo Hyperresponsivity of spontaneously hypertensive rat to indirect measurement of blood pressure chuang c. chiueh and irwin j. kopin a simple method for recording the electrocardiogram and heart rate from conscious animals By j. b. farmer and g. p. levy Br. J. Pharmac . Chemother . (1968), 32, 193-200. Measurement of invasive blood pressure in rats Subramani Parasuraman  and  Ramasamy Raveendran A Simple Device for Invasive Measurement of Arterial Blood Pressure and ECG in the Anesthesized Rat V . L. Ordodi 1 , F. A. Mic 1,3 , A. A. Mic 1 , O. Toma 2 , D. Sandesc 2 , V. Paunescu 1