The effect of methylpentynol and methylpentynol carbamate on the perfused superior cervical ganglion of the cat / by E. Marley and W.D.M. Paton.

  • Marley, E.
Date:
[1959?]
Catalogue details

Licence: In copyright

Credit: The effect of methylpentynol and methylpentynol carbamate on the perfused superior cervical ganglion of the cat / by E. Marley and W.D.M. Paton. Source: Wellcome Collection.

    4/8 page 304
    2 mg. MpC S 15 s 5 mg. MpC Fig. 1.—Cat, 1.7 kg.; chloralose anaesthesia. Perfused superior cervical ganglion preparation. Effect of various doses of methylpentynol carbamate (MpC) given intra-arterially on the contracture of the nictitating membrane excited by stimulation of the cervical sympathetic sustained for 3 min. at 10 sec. (at S). Note also small contraction elicited by methylpentynol carbamate. Time, min. ganglionic response is preserved (Marley, 1959) but the response of the intermittently stimulated nictitating membrane was only reduced by the intravenous infusion of very large doses (1,800 mg.) of either drug. With the perfused ganglion, likewise relatively large doses (1 to 5 mg.) were needed. In this preparation, injections into the perfusion cannula of the carbamate, but not of methylpentynol itself, sometimes produced a brief contraction of the nictitating membrane before the ganglionic block appeared (Fig. 1). This was never seen with injections to the blood-bathed ganglion, nor did the carbamate ever enhance the contraction produced by electrical stimulation of the cervical sympathetic. The contraction produced by the carbamate was not accompanied by release of acetylcholine in the perfusate. If the ganglion was stimulated by acetylcholine injected into the perfusion cannula (eserine being absent from the perfusing fluid), the response of the nictitating membrane was transiently diminished by previous doses of 2.0 mg. methyl¬ pentynol or the carbamate into the perfusate, although the response to preganglionic stimulation was unaffected (Fig. 2). The response to injected acetylcholine was thus more readily antagonized than that in normal transmission. The acetylcholine response usually returned to normal within 3 to 6 min. after giving either drug. If the preganglionic response was reduced by higher
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