TY - JOUR
T1 - Baroreceptor sensitivity of rat supraoptic vasopressin neurons involves noncholinergic neurons in the DBB
AU - Grindstaff, Ryan J.
AU - Grindstaff, Regina R.
AU - Cunningham, J. Thomas
PY - 2000
Y1 - 2000
N2 - 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 μg/μl) in the DBB. Baroreceptor sensitivity of neurons was tested with brief phenylephrine-induced (10 μg/10 μl 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.
AB - 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 μg/μl) in the DBB. Baroreceptor sensitivity of neurons was tested with brief phenylephrine-induced (10 μg/10 μl 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.
KW - Arterial baroreceptors
KW - Perinuclear zone
KW - Supraoptic nucleus
UR - http://www.scopus.com/inward/record.url?scp=0033672560&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.2000.279.5.r1934
DO - 10.1152/ajpregu.2000.279.5.r1934
M3 - Article
C2 - 11049879
AN - SCOPUS:0033672560
SN - 0363-6119
VL - 279
SP - R1934-R1943
JO - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
JF - American Journal of Physiology - Regulatory Integrative and Comparative Physiology
IS - 5 48-5
ER -