Where should you inject furosemide in a rat? - briefly
Administer furosemide intraperitoneally for routine systemic dosing, or inject it intravenously through the tail vein when rapid plasma concentrations are required.
Where should you inject furosemide in a rat? - in detail
Furosemide can be administered to a laboratory rat by several routes, each requiring specific anatomical landmarks and technique.
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Intraperitoneal injection
Site: lower right quadrant of the abdomen, avoiding the liver and intestines.
Procedure: insert a 25‑27 G needle at a shallow angle (≈30°) through the skin and peritoneum, aspirate to confirm entry, then deliver the dose.
Volume: ≤2 mL/kg body weight; typical doses range from 1–5 mg/kg. -
Tail‑vein intravenous injection
Site: dorsal surface of the lateral tail vein, visible after warming the tail (37–38 °C) for 1–2 min.
Procedure: use a 30‑31 G insulin syringe, bevel up, insert bevel parallel to the vein, advance until blood flashback occurs, then inject slowly.
Volume: ≤0.5 mL; recommended dose 1–2 mg/kg. -
Subcutaneous injection
Site: loose skin over the scruff (dorsal neck region) or the flank.
Procedure: lift a fold of skin, insert a 25‑27 G needle at a 45° angle, release the skin and inject.
Volume: ≤1 mL/kg; dose typically 1–5 mg/kg. -
Intramuscular injection (less common)
Site: hind‑limb quadriceps muscle, identified by palpating the thigh.
Procedure: use a 25‑27 G needle, insert perpendicularly to a depth of 0.5–1 cm, inject slowly.
Volume: ≤0.2 mL; dose similar to other routes.
Key procedural considerations:
- Aseptic technique – sterilize the injection site with 70 % ethanol; use sterile needles and syringes.
- Animal handling – restrain the rat gently to minimize stress; use a calibrated restrainer or manual grip.
- Needle selection – choose gauge based on volume and route; smaller gauges reduce tissue trauma.
- Post‑injection monitoring – observe for signs of distress, hemorrhage, or injection site reaction for at least 15 min.
Selecting the appropriate route depends on experimental goals, required absorption speed, and animal welfare. Intraperitoneal delivery offers rapid systemic exposure with minimal technical difficulty, while tail‑vein injection provides the fastest onset but demands skill in vein visualization. Subcutaneous administration is suitable for slow release, and intramuscular injection is reserved for specific pharmacokinetic studies.