Unilateral Cervical Sympathectomy Attenuates Hypertensive Responses Induced by Intracerebroventricular Administration of Choline in Rats.

Song,  Ho Kyung; Jang,  Yeon; Park,  Soo Seog

doi:2001.40.1.82

Experimental Research Article

Korean Journal of Anesthesiology 2001;40(1):82-88.
DOI: https://doi.org/10.4097/kjae.2001.40.1.82

Unilateral Cervical Sympathectomy Attenuates Hypertensive Responses Induced by Intracerebroventricular Administration of Choline in Rats.

Ho Kyung Song, Yeon Jang, Soo Seog Park

Department of Anesthesiology, Catholic University, Medical College, Inchon, Korea.

Abstract

BACKGROUND
Brain acetylcholine is an important neurotransmitter in the control of blood pressure. Pharmacological activation of central cholinergic receptors by intracerebroventricular (ICV) administration of choline resulted in a marked pressure response in hypotensive experimental models, and the pressure response was associated with an increase in plasma vasopressin levels. The aim of this study was to determine whether a unilateral cervical sympathectomy affects the pressure response induced by ICV choline.
METHODS
Rats were prepared with a cervical sympathectomy or with a sham operation and a 23 G cannula was implanted into the lateral cerebral ventricle. They were divided into three groups according to the pre-treated condition and the solution injected into the lateral cerebral ventricle; group 1 (ICV saline after sham operation), group 2 (ICV choline after sham operation), group 3 (ICV choline after cervical sympathectomy). Following the recovery period, pressure response was monitored for 50 min after injecting ICV choline or saline and plasma vasopressin levels were also assessed with an EIA kit at preinjection time, 10 min, and 50 min after ICV injection.
RESULTS
The baseline systolic blood pressure was 120.6 +/- 3.9 mmHg in group 3 and 121.7 +/- 9.0 mmHg in group 2 and there was no significant difference. The pressure response to ICV choline became evident within 1 min and reached a maximum magnitude in 10 min in both groups. Compared to the sham operated rats (group 2), the pressure response to ICV choline was significantly attenuated in sympathectomized rats (p < 0.05). However, the plasma vasopressin levels were not significantly affected by ICV choline or a cervical sympathectomy.
CONCLUSIONS
While the unilateral cervical sympathectomy itself did not have any effect on bloodpressure, it attenuated the pressure response to ICV choline. A unilateral cervical sympathectomy may attenuate the hypertensive response which is caused by an increased central cholinergic neurotransmission.

Key Words: Animals: rats; Hormones: vasopressin; Measurement techniques: blood pressure; Pharmacology: acetylcholine; choline; Sympathetic nervous system: cervical sympathectomy