Abstract
Both natural and synthetic peroxides have been shown to enhance sympathetic neurotransmission in the bovine isolated iris (Opere et al., IOVS 37: No. 2663, 1996). Purpose. To investigate the role of intracellular calcium ([Ca++]i) in peroxide-induced potentiation of adrenergic ncurosecretion from the bovine iris. Methods. Herni-irides were isolated from bovine eyeballs and prepared for studies of field-stimulated [3H]-norepinephrine ([3H]NE) release using the supervision method. Results. Regulators of [Ca++], such as BAPTA AM (10 μM), thapsigargin (THAP, 10 MM), ruthenium red (RR, 30 μM) and oligomycin (OLIGO, 30 μM) inhibited electrically-evoked [3H]NE overflow bv 54%, 30%, 30% and 26%, lespectively. H2O2 (0.3 mM) produced a 42% increase in evoked [3H|NE release that was blocked bv RR (30 μM). Conversely, OLIGO (30 μM) potentiated H2O2 (0-3 mM)-induced enhancement of field-stimulated [3H]NE overflow bv 89%. Interestingly, both BAPTA AM (10 μM) and THAP (10 μM) had no effect on the peroxide response. Conclusions. Mitochondrial Ca++ stores are involved in H2O2,-induced potentiation of stimulated |3H]NE release. However, changes in both eytosolic and endoplasmic reticulum Ca++ stores may not affect peroxide-induced enhancement of sympathetic neurotransmission in the bovine iris.
| Original language | English |
|---|---|
| Journal | Investigative Ophthalmology and Visual Science |
| Volume | 38 |
| Issue number | 4 |
| State | Published - 1997 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Ophthalmology
Cite this
Role of intracellular calcium in peroxide-induced potentiation of norepinephrine release from bovine irides. / Opere, Catherine A.; Ohia, S.
In: Investigative Ophthalmology and Visual Science, Vol. 38, No. 4, 1997.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Role of intracellular calcium in peroxide-induced potentiation of norepinephrine release from bovine irides
AU - Opere, Catherine A.
AU - Ohia, S.
PY - 1997
Y1 - 1997
N2 - Both natural and synthetic peroxides have been shown to enhance sympathetic neurotransmission in the bovine isolated iris (Opere et al., IOVS 37: No. 2663, 1996). Purpose. To investigate the role of intracellular calcium ([Ca++]i) in peroxide-induced potentiation of adrenergic ncurosecretion from the bovine iris. Methods. Herni-irides were isolated from bovine eyeballs and prepared for studies of field-stimulated [3H]-norepinephrine ([3H]NE) release using the supervision method. Results. Regulators of [Ca++], such as BAPTA AM (10 μM), thapsigargin (THAP, 10 MM), ruthenium red (RR, 30 μM) and oligomycin (OLIGO, 30 μM) inhibited electrically-evoked [3H]NE overflow bv 54%, 30%, 30% and 26%, lespectively. H2O2 (0.3 mM) produced a 42% increase in evoked [3H|NE release that was blocked bv RR (30 μM). Conversely, OLIGO (30 μM) potentiated H2O2 (0-3 mM)-induced enhancement of field-stimulated [3H]NE overflow bv 89%. Interestingly, both BAPTA AM (10 μM) and THAP (10 μM) had no effect on the peroxide response. Conclusions. Mitochondrial Ca++ stores are involved in H2O2,-induced potentiation of stimulated |3H]NE release. However, changes in both eytosolic and endoplasmic reticulum Ca++ stores may not affect peroxide-induced enhancement of sympathetic neurotransmission in the bovine iris.
AB - Both natural and synthetic peroxides have been shown to enhance sympathetic neurotransmission in the bovine isolated iris (Opere et al., IOVS 37: No. 2663, 1996). Purpose. To investigate the role of intracellular calcium ([Ca++]i) in peroxide-induced potentiation of adrenergic ncurosecretion from the bovine iris. Methods. Herni-irides were isolated from bovine eyeballs and prepared for studies of field-stimulated [3H]-norepinephrine ([3H]NE) release using the supervision method. Results. Regulators of [Ca++], such as BAPTA AM (10 μM), thapsigargin (THAP, 10 MM), ruthenium red (RR, 30 μM) and oligomycin (OLIGO, 30 μM) inhibited electrically-evoked [3H]NE overflow bv 54%, 30%, 30% and 26%, lespectively. H2O2 (0.3 mM) produced a 42% increase in evoked [3H|NE release that was blocked bv RR (30 μM). Conversely, OLIGO (30 μM) potentiated H2O2 (0-3 mM)-induced enhancement of field-stimulated [3H]NE overflow bv 89%. Interestingly, both BAPTA AM (10 μM) and THAP (10 μM) had no effect on the peroxide response. Conclusions. Mitochondrial Ca++ stores are involved in H2O2,-induced potentiation of stimulated |3H]NE release. However, changes in both eytosolic and endoplasmic reticulum Ca++ stores may not affect peroxide-induced enhancement of sympathetic neurotransmission in the bovine iris.
UR - http://www.scopus.com/inward/record.url?scp=0010410115&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0010410115&partnerID=8YFLogxK
M3 - Article
VL - 38
JO - Investigative Ophthalmology and Visual Science
JF - Investigative Ophthalmology and Visual Science
SN - 0146-0404
IS - 4
ER -