Baroreceptor sensitivity of rat supraoptic vasopressin neurons involves noncholinergic neurons in the DBB.
Am J Physiol Regul Integr Comp Physiol
; 279(5): R1934-43, 2000 Nov.
Article
in En
| MEDLINE
| ID: mdl-11049879
ABSTRACT
Previous studies suggest that cholinergic neurons in the diagonal band of Broca (DBB) participate in the baroreceptor-mediated inhibition of phasic vasopressin neurons in the supraoptic nucleus (SON). To test this hypothesis, extracellular recordings were obtained from putative vasopressin SON neurons of anesthetized rats injected with the cholinergic immunotoxin 192 IgG-saporin (0.8 microg/microl) in the DBB. Baroreceptor sensitivity of neurons was tested with brief phenylephrine-induced (10 microg/10 microl iv) increases in blood pressure of at least 40 mmHg. In rats injected with vehicle or unconjugated saporin, 19 of 21 and 18 of 20 phasic neurons, respectively, were inhibited by increased blood pressure. In rats injected with 192 IgG-saporin, which significantly reduced the number of choline acetyltransferase (ChAT)-positive DBB neurons, 33 of 36 phasic neurons were inhibited. Normal rats and rats with DBB saporin injections received rhodamine bead injections into the perinuclear zone (PNZ) to retrogradely label DBB neurons, and their brains were stained for ChAT. ChAT-positive DBB neurons were not retrogradely labeled from the PNZ. Together, these results indicate that the pathway relaying baroreceptor information to the SON involves noncholinergic DBB neurons.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pressoreceptors
/
Supraoptic Nucleus
/
Vasopressins
/
Diagonal Band of Broca
/
Neurons
Type of study:
Diagnostic_studies
Limits:
Animals
Language:
En
Journal:
Am J Physiol Regul Integr Comp Physiol
Journal subject:
FISIOLOGIA
Year:
2000
Document type:
Article
Affiliation country:
United States