Direct projections from the periaqueductal gray to the pontine micturition center (M-region). An anterograde and retrograde tracing study in the cat

  title={Direct projections from the periaqueductal gray to the pontine micturition center (M-region). An anterograde and retrograde tracing study in the cat},
  author={Bertil F. M. Blok and Gert Holstege},
  journal={Neuroscience Letters},
Micturition is a spino-bulbo-spinal reflex. The bulbospinal part of this reflex is formed by the projections from the M-region, also called the pontine micturition center or Barrington's nucleus, to the preganglionic parasympathetic motoneurons in the sacral cord innervating the bladder. In respect to the spino-bulbar part of the micturition reflex, our group recently showed that the sacral cord projections to the brainstem terminate mainly in the periaqueductal gray (PAG). In this study it was… 
Direct projections from the periaqueductal gray to pontine micturition center neurons projecting to the lumbosacral cord segments: an electron microscopic study in the rat
The results indicate that the ventrolateral part of the PAG is implicated in regulation of the micturition reflex.
Ultrastructural evidence for a paucity of projections from the lumbosacral cord to the pontine micturition center or M‐region in the cat: A new concept for the organization of the micturition reflex with the periaqueductal gray as central relay
It was investigated in cats whether monosynaptic projections from lumbosacral neurons to the M‐region indeed exist, and it was demonstrated that the lateral part of the periaqueductal gray contains neurons projecting to theM‐region.
Afferent projections to the pontine micturition center in the cat
All other parts of the brain that influence micturition have no direct connection with the PMC, as indicated by results in 67 cats.
Direct projections from the lumbosacral spinal cord to Barrington's nucleus in the rat: A special reference to micturition reflex
Clear evidence is provided for a direct projection from the spinal parasympathetic and dorsal commissural nuclei to Barrington's nucleus that could subserve conveying bladder‐filling information from the lumbosacral cord to Barlington's nucleus in the micturition reflex of the rat.
Is the periaqueductal gray an essential relay center for the micturition reflex pathway in the cat?
It is demonstrated that Barrington's nucleus is essential, but the PAG is not essential, for evoking micturition.
Two pontine micturition centers in the cat are not interconnected directly: Implications for the central organization of micturition
The M and L‐regions have direct long fiber projections to the motoneurons of the bladder muscle and the external urethral sphincter, but they do not influence one another through direct pathways.
Ultrastructural evidence for a direct pathway from the pontine micturition center to the parasympathetic preganglionic motoneurons of the bladder of the cat
It is demonstrated that neurons in the PMC indeed project to preganglionic bladder motoneurons after Wheat germ agglutinin horseradish peroxidase was injected and cholera toxin B subunit was injected in the bladder wall.
Micturition-suppressing region in the periaqueductal gray of the mesencephalon of the cat.
  • A. Numata, T. Iwata, +5 authors H. Kakizaki
  • Biology, Medicine
    American journal of physiology. Regulatory, integrative and comparative physiology
  • 2008
The results suggest that the dorsolateral margin of the rostral PAG includes the micturition-suppressing region that seems to have neural connections with the PMC.
Evidence for a periaqueductal gray–nucleus retroambiguus–spinal cord pathway in the rat
The results indicate that in the rat a periaqueductal gray nucleus retroambiguus spinal cord projection also exists, which may be of crucial importance for the study of the anatomical and physiological framework of respiration, vocalization, and female and male reproductive behaviour in this animal.
Neurons in the guinea pig (Cavia porcellus) lateral lumbosacral spinal cord project to the central part of the lateral periaqueductal gray matter
Results show that neurons in the lateral part of the lumbosacral spinal cord project to the central parts of the PAG in guinea pig, suggesting that this pathway may convey information about the level of bladder filling to the PG.


Projections from the periaqueductal gray to the rostromedial pericoerulear region and nucleus locus coeruleus: Anatomic and physiologic studies
The functional anatomy of projections from PAG to the dorsolateral pontine tegmentum is investigated and the organization and synaptic influence of PAG on neurons in the rostromedial pericoerulear region and in LC proper is assessed.
Location and morphology of parasympathetic preganglionic neurons in the sacral spinal cord of the cat revealed by retrograde axonal transport of horseradish peroxidase
Investigation of the distribution and morphology of preganglionic neurons in the sacral parasympathetic nucleus of the cat and the results of other investigations indicate that the SPN has a viscerotopic organization wherein the colon is innervated primarily by cells in the dorsal band and the urinary bladder is innerved primarily bycells in the lateral band.
1. Destruction of a small part of the brain just ventral to the internal edge of the superior cerebellar peduncle from the level of the middle of the motor nucleus of the fifth nerve behind to the
Anatomical and physiological observations on suprapinal control of bladder and urethral sphincter muscles in the cat
In 15 cats injections of 3H‐leucine made in the pontine tegmentum resulted in specific projections to the sacral intermediomedial and intermediolateral cell groups, which contains preganglionic parasympathetic neurons that form the motor supply of the detrusor muscle of the bladder.
Some anatomical observations on the projections from the hypothalamus to brainstem and spinal cord: An HRP and autoradiographic tracing study in the cat
  • G. Holstege
  • Biology, Medicine
    The Journal of comparative neurology
  • 1987
The hypothalamus is closely involved in a wide variety of behavioral, autonomic, visceral, and endocrine functions, and descending pathways are investigated by horseradish peroxidase and autoradiographic tracing techniques.
The Physiology of the Lower Urinary Tract
This book discusses structure and Innervation in the Human, Comparative Neuromorphology in Animals, and the role of Higher Levels of the Central Nervous System in Bladder Control.
A tetramethylbenzidine/tungstate reaction for horseradish peroxidase histochemistry.
  • R. Weinberg, S. V. van Eyck
  • Chemistry, Medicine
    The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society
  • 1991
A new modification of this reaction using ammonium paratungstate stabilizer retains high sensitivity while permitting the reaction to be performed at pH 6.0 in isotonic solutions, allowing Nissl-stained sections to retain their peroxidase labeling.