What is the clinical evidence from this study?

Study design: Other. Population: Coronary arterial microvascular tone (n=37). Intervention: Mastoparan vs. Baseline / various pretreatments. Primary outcome: Coronary arterial microvascular dilation.

What question did this study set out to answer?

This study aims to explore how pertussis toxin-sensitive G protein activation affects coronary microvascular dilation in different-sized vessels.

January 1, 1997Circulation Research

Mechanisms of Coronary Microvascular Dilation Induced by the Activation of Pertussis Toxin–Sensitive G Proteins Are Vessel-Size Dependent

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Key result

Topically applied mastoparan produced homogeneous, concentration-dependent coronary microvascular dilation (up to 16.7% in small and 15.5% in large vessels), with mechanisms dependent on vessel size.

Why the study?

Does activation of pertussis toxin-sensitive G proteins induce coronary microvascular dilation in a vessel-size dependent manner in an in vivo dog model?

Population

37 open-chest anesthetized dogs in vivo

Comparison

Topically applied mastoparan with or without… vs Baseline microvascular tone and comparison…

Design

Preclinical

Authors

TKTatsuya KomaruMitsubishi Heavy Industries (Germany)TTToshinori TanikawaTohoku University ASAkihiko SugimuraTohoku University

Discussion

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Implication

Should not inform therapy; leaves open translation of size-dependent G-protein coronary dilation to humans.

Key Points

This study aims to explore how pertussis toxin-sensitive G protein activation affects coronary microvascular dilation in different-sized vessels.
Investigated effects in 37 open-chest anesthetized dogs using fluorescence coronary microangiography.
Microvessels divided into small (≤130 microns) and large (>130 microns); treated with mastoparan at varying concentrations.
Examined the role of nitric oxide and potassium channels in mediating microvascular dilation.
Mastoparan induced dilation in small microvessels: 7.9% (10 mumol/L), 10.3% (30 mumol/L), 16.7% (100 mumol/L); in large microvessels: 5.3%, 9.8%, 15.5% respectively.
Pretreatment with PTX reversed dilation to constriction in both groups; blockade of nitric oxide impacted large but not small microvessels.
Glibenclamide affected the response to mastoparan differently based on vessel size, confirming size-dependent mechanisms.

Structured PICO

Does activation of pertussis toxin-sensitive G proteins induce coronary microvascular dilation in a vessel-size dependent manner in an in vivo dog model?

Population

37 open-chest anesthetized dogs in an in vivo study of coronary arterial microvascular tone.

Intervention

Topically applied mastoparan (G protein activator, 10, 30, and 100 mumol/L) with or without pretreatment with pertussis toxin (PTX), NG-nitro-L-arginine (LNNA), glibenclamide, or charybdotoxin

Comparator

Baseline microvascular tone and comparison between small (<= 130 microns) and large (> 130 microns) microvessels

Outcome

Coronary arterial microvascular tone (dilation or constriction)surrogate

Activation of pertussis toxin-sensitive G proteins produces coronary microvascular dilation that is vessel-size dependent, mediated by nitric oxide in large microvessels and ATP-sensitive K+ channels in small microvessels.

Cite This Study

Komaru et al. (1997) studied Coronary arterial microvascular tone (n=37). Mastoparan vs. Baseline / various pretreatments was evaluated on Coronary arterial microvascular dilation. Topically applied mastoparan produced homogeneous, concentration-dependent coronary microvascular dilation (up to 16.7% in small and 15.5% in large vessels), with mechanisms dependent on vessel size.

synapsesocial.com/papers/6a23974b9e1c90a91c08f273 https://doi.org/10.1161/01.res.80.1.1

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Mechanisms of Coronary Microvascular Dilation Induced by the Activation of Pertussis Toxin–Sensitive G Proteins Are Vessel-Size Dependent

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Mechanisms of Coronary Microvascular Dilation Induced by the Activation of Pertussis Toxin–Sensitive G Proteins Are Vessel-Size Dependent

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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Also Consider