PMID- 1965797
OWN - NLM
STAT- MEDLINE
DCOM- 19910723
LR  - 20190402
IS  - 0304-4920 (Print)
IS  - 0304-4920 (Linking)
VI  - 33
IP  - 4
DP  - 1990
TI  - Tonic reduction in central alpha 2-adrenoceptor activity by endogenous 
      angiotensin III in the rat.
PG  - 367-83
AB  - We evaluated the possible interactions between central alpha 2-adrenoceptors and 
      endogenous angiotensin III (AIII) in Sprague-Dawley rats anesthetized with 
      pentobarbital sodium (50 mg/kg, i.p.). The cardiovascular suppressive effects of 
      the alpha 2-adrenoceptor agonist, guanabenz, were used as our experimental index 
      for alpha 2-adrenoceptor activity. Intracerebroventricular (i.c.v.) 
      administration of AIII (100 or 200 pmol) attenuated the hypotensive and negative 
      inotropic and chronotropic actions of guanabenz (100 micrograms/kg, i.v.). 
      Blocking the endogenous activity of the heptapeptide with its specific 
      antagonist, Ile7-AIII (50 or 100 nmol, i.c.v.), on the other hand, potentiated 
      the circulatory inhibitory efficacy of the aminoguanidine compound. These 
      modulatory effects were essentially duplicated by bilateral microinjection of 
      AIII (20 or 40 pmol) or Ile7-AIII (10 or 20 nmol) into the nucleus reticularis 
      gigantocellularis (NRGC), a medullary site that is critically involved in the 
      cardiovascular suppressive actions of guanabenz. I.c.v. injection of bestatin 
      (200 nmol) also reduced the circulatory depressive potency of guanabenz. This 
      effect was respectively enhanced and reduced when the aminopeptidase inhibitor 
      was given simultaneously with AIII (200 pmol) and Ile7-AIII (100 nmol). These 
      results suggest that the endogenous AIII may exert a tonic inhibition on the 
      alpha 2-adrenoceptors in in the NRGC that are involved in cardiovascular 
      regulation.
FAU - Lee, H C
AU  - Lee HC
AD  - Institute of Pharmacology, National Yang-Ming Medical College, Taipei, Taiwan, 
      Republic of China.
FAU - Chan, J Y
AU  - Chan JY
FAU - Chan, S H
AU  - Chan SH
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - India
TA  - Chin J Physiol
JT  - The Chinese journal of physiology
JID - 7804502
RN  - 0 (Receptors, Adrenergic, alpha)
RN  - 12687-51-3 (Angiotensin III)
RN  - EC 3.6.1.- (GTP-Binding Proteins)
RN  - GGD30112WC (Guanabenz)
RN  - GMW67QNF9C (Leucine)
RN  - I0J33N5627 (ubenimex)
SB  - IM
MH  - Angiotensin III/pharmacology/*physiology
MH  - Animals
MH  - Brain/drug effects/*physiology
MH  - GTP-Binding Proteins/physiology
MH  - Guanabenz/pharmacology
MH  - Hemodynamics/drug effects
MH  - Injections, Intraventricular
MH  - Leucine/analogs & derivatives/pharmacology
MH  - Male
MH  - Rats
MH  - Rats, Inbred Strains
MH  - Receptors, Adrenergic, alpha/drug effects/*physiology
EDAT- 1990/01/01 00:00
MHDA- 1990/01/01 00:01
CRDT- 1990/01/01 00:00
PHST- 1990/01/01 00:00 [pubmed]
PHST- 1990/01/01 00:01 [medline]
PHST- 1990/01/01 00:00 [entrez]
PST - ppublish
SO  - Chin J Physiol. 1990;33(4):367-83.