The rat anococcygeus muscle and its response to nerve stimulation and to some drugs

  • 13


    Mendeley users who have this article in their library.
  • 304


    Citations of this article.


1. A new smooth muscle preparation, the rat anococcygeus muscle, is described. The muscle is paired, thin, consists of smooth muscle only and the muscle cells are organized in parallel bundles. It has a dense adrenergic innervation distributed throughout the muscle but apparently no cholinergic innervation. The muscles are easily isolated.2. The muscle contracts to noradrenaline, acetylcholine, furmethide, 5-hydroxytryptamine, but not to histamine. Isoprenaline produces contraction at high concentrations. The effects of noradrenaline and acetylcholine are blocked by phentolamine and atropine respectively. The response to isoprenaline is little affected by propranolol.3. The muscle contracts in response to field stimulation or stimulation of extrinsic nerves. This response is completely blocked by phentolamine but unaffected by hexamethonium or atropine.4. Guanethidine 10(-6)-5 x 10(-6)M blocks the motor response to nerve stimulation and potentiates that to noradrenaline. Higher concentrations of guanethidine raise tone. In the presence of raised tone, field stimulation produces an inhibitory response insensitive to hexamethonium but abolished by tetrodotoxin 2 x 10(-7) g/ml. This inhibitory response to stimulation can also be shown after other drugs which raise tone.5. The inhibitory response to nerve stimulation is not mimicked by acetylcholine, isoprenaline or ATP, nor blocked by atropine, phentolamine, phenoxybenzamine, propranolol, hexamethonium or lysergic acid diethylamide.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Get full text



Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free