Blood sampling from the cranial vena cava in the Norway rat (Rattus norvegicus)

This paper describes blood sampling from the cranial vena cava (CVC) in the Norway rat. In order to limit stress, the blood sampling should be done under short-term inhalation anaesthesia, for example, an oxygen/isoflurane mixture. The injection site is just cranial to the first rib, 0.3-0.8 cm lateral to the manubrium when the animal is in dorsal recumbency. The needle, attached to a syringe, is inserted at 30 degrees in the direction of the opposite femoral head. After penetration of the skin, negative pressure is developed in the syringe and the insertion of the needle is continued for another 0.2-1 cm in the given direction until blood begins to flow. The amount of blood sampled ranges from 0.8 to 2.5 mL depending on the body weight of the patient. A trial on 50 rats aged 5-24 months included 25 rats sampled once, eight rats sampled twice with an interval of seven days, 11 rats sampled twice with an interval of three weeks and four rats sampled four times with intervals of four weeks--a total of 87 blood samplings. The serious complications quoted in association with blood sampling from the CVC in other experimental animals (vascular lacerations, heart puncture, serious haemorrhage, tracheal and throat trauma) were not observed in our study. There were only four blood samplings (4.5%) with mild haemorrhage from the injection site, due to erroneous sampling from the jugular vein.     

Non-surgical cannulation of the vena cava for chronic blood collection in mature swine.

A nonsurgical cannulation technique for blood collections from mature swine was evaluated. Primiparous Yorkshire-Landrace sows (n = 6) received an indwelling jugular vein cannulae for 7 days duration. Recannulation was performed at monthly intervals for a total of 14 months. During cannulation, sows were restrained in a standing position using a rope snout snare. A 12-gauge by 10 cm needle was inserted into the jugular vein. Sterilized polyvinyl chloride tubing was advanced through the needle into the vein and a blunted 18-gauge needle and attached intermittent injection hub was inserted into the free end of the tubing. Surgical tape was used to form a butterfly on the tubing by suturing the tape to the animals' skin. Foam padding, livestock cement, and elastic tape helped to keep the tubing in position. Problems with cannulae patency and maintenance were few. No behavioral problems or systemic signs of illness were noted and necropsy examinations performed after the final cannulation revealed few abnormalities associated with chronic intermittent cannulation. This technique provides a safe, quick, effective means for multiple and repeated cannulae placement for blood collection from mature swine with minimal effects on the animal and without the risks associated with surgical techniques.     

Blood collection from the tail of a rat

Techniques for blood collection from the rat include puncture of the heart, retro-orbital plexus, jugular vein, saphenous vein, tail blood vessels, carotid artery, abdominal aorta, and vena cava. Most techniques (except saphenous vein and tail blood vessel puncture) require anesthesia. The following discussion focuses on two methods of blood collection - ventral tail artery puncture and dorsal or lateral tail vein puncture.     

Retro-orbital technique for blood collection from the ferret (Mustela putorius furo)

Blood samples were obtained from anesthetized ferrets of various ages, by venipuncture of the retro-orbital plexus with a heparinized capillary pipette. It is recommended that a cumulative collection of 20% of total blood volume not be exceeded for any two week period. This technique, when carefully performed on alternate orbits and at a frequency dictated by body weight and volume of blood needed, has been used repeatedly for months without apparent harm or distress to the animal.     

Refractoriness of the sheep superior vena cava myocardial sleeve

The cardiomyocytes in the superior vena cava (SVC) myocardial sleeve have distinct action potentials and ionic current profiles, but the refractoriness of these cells has not been reported. Using standard intracellular microelectrode techniques, we demonstrated in sheep that the effective refractory period (ERP) of the cardiomyocytes in the SVC (114.7 +/- 6.5 ms) is shorter than that in the inferior vena cava (IVC) (166.7 +/- 6.2 ms), right atrial free wall (RAFW) (201.0 +/- 6.0 ms) and right atrial appendage (RAA) (203.1 +/- 5.8 ms) (P < 0.05). The right atrial cardiomyocyte ERP was heterogeneously shortened by acetylcholine, a muscarinic type 2 receptor (M(2)R) agonist. After perfusion with 15 microM acetylcholine, the shortest ERP occurred in the SVC (the ERP in the SVC, IVC, RAFW and RAA was 53.6 +/- 2.7, 98.9 +/- 2.2, 121.8 +/- 6.0 and 109.7 +/- 5.1 ms, respectively; P < 0.05). Carbachol (1 microM), another M(2)R agonist, produced a similar effect as acetylcholine. Furthermore, we used methoctramine, a M(2)R blocker, 4-DAMP, a muscarinic type 3 receptor (M(3)R) blocker, and tropicamide, a muscarinic type 4 receptor (M(4)R) blocker to inhibit the acetylcholine-induced ERP shortening of SVC cardiomyocytes, and found that the 50% inhibitory concentration for methoctramine, 4-DAMP and tropicamide was 5.91, 45.72 and 80.34 nM, respectively. Therefore, we conclude that the sheep SVC myocardial sleeve is a unique electrophysiological region of the right atrium with the shortest ERP both under physiological condition and under cholinergic agonist stimulation. M(2)R might play a major role in the response of the SVC myocardial sleeve to parasympathetic nerve tone. The association between the distinct refractoriness in SVC and atrial fibrillation originating from the region deserves further investigation.     

Ostium of the collection stem of the anterior cardiac veins (vv. cardiacae anteriores) in the vena cava, inferior

In 1 of 150 studied cases, we found the collection stem of anterior cardiac veins that emptied into the inferior vena cava. This collection stem had eight tributaries: two right atrial veins, five anterior cardiac veins and a right marginal vein. The caliber of the collection stem was increasing gradually from its beginning (2.8 mm) to its orifice (4.5 mm). The orifice of the collection stem was in the inferior vena cava, at a distance of 10 mm from its ostial valve, and was itself provided with a semilunar valve.