Relationship between cytosolic Ca2+ level and contractile tension in canine basilar artery of chronic vasospasm.

Abstract

In order to study the role of the Ca2+/calmodulin/myosin light chain kinase system in the development of chronic vasospasm caused by subarachnoid hemorrhage, the cytosolic Ca2+ level ([Ca2+]i), measured with fura-2, a fluorescent Ca2+ indicator, and contractile tension were measured simultaneously, and their quantitative correlation was examined in basilar arterial tissue obtained from the canine "two-hemorrhage" model. Sixteen adult mongrel dogs were divided into two groups, control (n = 8) and vasospasm (n = 8), and were killed 7 days after the first experimental subarachnoid hemorrhage. In basilar arterial tissue loaded with fura-2, 1) [Ca2+]i in the resting condition was not significantly different between the two groups; 2) the increment in [Ca2+]i induced by 40 mmol/L K+ stimulation was significantly smaller in vasospastic tissue (P < 0.01); and 3) 40 mmol/L K(+)-induced tension development per cross-sectional area for a fixed increment in [Ca2+]i was significantly greater in vasospastic tissue (P < 0.01). In tissue not loaded with fura-2, active myogenic tone, which was tentatively represented by the ratio of tonus relaxed with 10(-4) mol/L papaverine to initial resting tone, was significantly greater in vasospastic tissue (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

• Authors: T Yamada, Y Tanaka, K Fujimoto, N Nakahara, S Shinoda, T Masuzawa
• Journal: Neurosurgery (Neurosurgery) Vol. 34 Issue 3 Pg. 496-503; discussion 503-4 (Mar 1994) ISSN: 0148-396X [Print] United States
• PMID: 8190226 (Publication Type: Journal Article)

Chemical References

• Potassium
• Calcium
• Fura-2

Topics

• Animals
• Basilar Artery (physiopathology)
• Calcium (metabolism)
• Cytosol (metabolism)
• Dogs
• Female
• Fura-2
• Ischemic Attack, Transient (physiopathology)
• Male
• Membrane Potentials (physiology)
• Muscle Contraction (physiology)
• Muscle Tonus (physiology)
• Muscle, Smooth, Vascular (physiopathology)
• Potassium (physiology)
• Subarachnoid Hemorrhage (physiopathology)