Atropine effects on the embryonic rat heart

✍ Scribed by Hall, E. K.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1959
• Tongue: English
• Weight: 475 KB
• Volume: 53
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030530105

✦ Synopsis

T W O FIGURES

There is diversity of opinion as to the nature of action of atropine on cardiac muscle. It is stated in some texts that atropine has slight and insignificant direct effects, in others. that small doses stimulate but that large doses depress. Nearly all authors agree that, in blocking acetylcholine (ACh) effects, the drug acts not upon the nerve endings but directly on the muscle fiber. These statements can evidently be tested by experiments on the embryonic (pre-neural) heart.

In the present investigation, it was observed that atropine had no chronotropic or inotropic effects on the embryonic rat heart, that low concentrations were effective in blocking high ACh concentrations, but that these blocking effects were tran- sitory and could no longer be demonstrated within 45 minutes.

MATERIALS AND METHODS a

The materials and methods were in general those of previous investigations (Hall, '51, '54, '55, '57). The 111/-day rat embryos were removed singly from the female to Krebs-Ringer solution at body temperature, where the hearts were dissected out under the binocular dissecting microscope.