title: Cardiovascular responses to intracerebroventricular infusion of artificial cerebrospinal fluid in anesthetized strain 13 guinea pigs.
abstract: The cardiovascular effects of constant intracerebroventricular infusion in anesthetized strain 13 guinea pigs were studied. Bilateral cerebroventricles of the animals were catheterized stereotaxically with two 20-gauge blunt needles, penetrating 5 to 6 mm into the skull. Baseline cerebroventricular pressure values were 1.3 +/- 0.6 mmHg. After artificial cerebrospinal fluid was infused into the left ventricle at 0.5 ml/h, left cerebroventricular pressure increased to 8.1 +/- 1.6 mmHg (P less than 0.01), while right cerebroventricular pressure reached 5.6 +/- 2.2 mmHg within 20 minutes. No significant changes in mean blood pressure or heart rate were observed. When intracerebroventricular infusion rate increased to 5.0 ml/h, cerebrospinal fluid pressures of left and right cerebroventricles increased to 40.0 +/- 4.8 and 38.4 +/- 4.7 mmHg within 10 minutes from baseline values of 1.5 +/- 0.5 and 1.7 +/- 0.7 mmHg, respectively. Simultaneously, mean blood pressure and heart rate increased from 72 +/- 4 to 101 +/- 9 mmHg and from 195 +/- 11 to 218 +/- 17 beats/min, respectively. However, 30 to 50 minutes later, mean blood pressure, heart rate, and cerebrospinal fluid pressure decreased abruptly, and two of four animals died. We suggest that this technique with a low infusion rate (less than 0.5 ml/h) can be used to deliver certain drugs into the brain ventricles directly without producing undesirable effects on blood pressure or heart rate.
authors.affiliation: Department of Clinical and Experimental Physiology, United States Army Medical Research Institute of Infectious Disease, Fort Detrick, Frederick, MD 21702-5011.
authors.forename: C T
authors.initials: CT
authors.lastname: Liu
authors.forename: Z M
authors.initials: ZM
authors.lastname: Guo
mesh_terms: D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D002555:Cerebrospinal Fluid / Q000502:physiology*; D015170:Cerebrospinal Fluid Pressure / Q000502:physiology*; D004195:Disease Models, Animal; D006168:Guinea Pigs; D006339:Heart Rate / Q000502:physiology*; D007276:Injections, Intraventricular