0
Laboratory and Animal Investigations |

A Pharmacologic Study on CO2 Responsiveness of Intracranial Pressure in Rats With Chronic Hypercapnia*

Tetsuri Kondo, MD; Miho Kumagai, MD; Futoshi Takei, MD; Yasuyo Ohta, MD, FCCP
Author and Funding Information

*From the Department of Medicine (Drs. Kondo, Kumagai, and Ohta) and the Department of Neurosurgery (Dr. Takei), Tokai University School of Medicine, Kanagawa, Japan. Supported by a Grant-in-Aid for Scientific Research (#09770426) from the Ministry of Education, Science, and Culture in Japan.

Correspondence to: Tetsuri Kondo, MD, Department of Medicine, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan; e-mail: tetsuri@is.icc.u-tokai.ac.jp



Chest. 1999;115(5):1402-1406. doi:10.1378/chest.115.5.1402
Text Size: A A A
Published online

Study objectives: To investigate intracranial pressure (ICP) changes and their mechanisms in chronic hypercapnia.

Design: After 12 male Wistar rats were maintained in CO2-mixed air (mean Paco2, 71.0 mm Hg) for 21 weeks, their ICP levels were measured during the breathing of 0, 5, 10, 12, and 14% CO2-mixed air before and after the IV administration of nitro-l-arginine methyl ester (l-NAME). The ICP responses to IV norepinephrine and IV adenosine were also tested. Ten rats that were maintained in room air served as the control group.

Results: The mean ICP in the study group (5.9 mm Hg) was not significantly different from the mean ICP in the control group. In the study group, the ICP response to changes in Paco2 was significantly blunted when compared to the response seen in the control group. In both groups, IV norepinephrine significantly increased the ICP. In the control group but not in the study group, IV l-NAME suppressed the ICP response to changes in Paco2. In both groups, IV adenosine significantly increased the ICP.

Conclusions: The ICP response to Paco2 was blunted in rats with chronic hypercapnia, and the mechanism of this reduced response may involve nitric oxide.

Abbreviations: Fico2 = fractional concentration of carbon dioxide in inspired gas; ICP = intracranial pressure; l-NAME = nitro-l-arginine methyl ester; MAP = mean arterial pressure; NO = nitric oxide

Figures in this Article

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Figures

Tables

References

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Sign In to Access Full Content

MEMBER & INDIVIDUAL SUBSCRIBER

Want Access?

NEW TO CHEST?

Become a CHEST member and receive a FREE subscription as a benefit of membership.

Individuals can purchase this article on ScienceDirect.

Individuals can purchase a subscription to the journal.

Individuals can purchase a subscription to the journal or buy individual articles.

Learn more about membership or Purchase a Full Subscription.

INSTITUTIONAL ACCESS

Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Find Similar Articles
CHEST Journal Articles
PubMed Articles
  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543