Receptors involved in nerve-mediated vasoconstriction in small arteries of the rat hepatic mesentery

Br J Pharmacol. 1998 Aug;124(7):1403-12. doi: 10.1038/sj.bjp.0701976.


1. We have investigated the neurotransmitters and receptor subtypes involved in nerve-mediated vasoconstriction in small arteries of the rat hepatic mesentery. 2. A dense sympathetic innervation was demonstrated using catecholamine histochemistry and antibodies against the synaptic vesicle protein synaptophysin. 3. Reverse transcription-polymerase chain reaction (RT-PCR) demonstrated very strong expression of the alpha1A-adrenergic, neuropeptide Y (NPY) Y1, P2X1- and P2X4-purinergic receptors, moderate expression of the alpha2B-adrenergic receptor and the purinergic P2X5- and P2X7-receptors and weak expression of the alpha1B-, alpha1D-, alpha2A- and alpha2C-adrenergic receptors and the P2X2- and P2X3-purinergic receptors. NPY2 and P2X6 receptor expression was absent. 4. Electrical field stimulation (10 Hz, 10 s) produced contractions which were abolished by tetrodotoxin (10(-6) M) and/or guanethidine (GE, 5 x 10(-6) M) and a combination of benextramine (10(-5) M) and alpha,beta-methylene ATP, (alpha,beta-mATP, 3 x 10(-6) M) or PPADS (10(-5) M). Selective alpah1-adrenergic receptor antagonists showed the potency order of prazosin > WB-4101 > 5-methyl-urapidil > BMY 7378. Yohimbine (10(-8) M, 10(-7) M), alpha,beta-mATP (3 x 10(-6) M) and PPADS (10(-5) M) each enhanced the response to nerve stimulation. 5. Some experiments demonstrated a slow neurogenic contraction which was abolished by GE or the selective NPY1 receptor antagonist 1229U91 (6 x 10(-7) M). 6. We conclude that nerve-mediated vasoconstriction results from the activation of postsynaptic alpha,beta-adrenergic and P2X-purinergic receptors and under some conditions, NPY1 receptors. Neurotransmitter release is modulated by presynaptic alpha2-adrenergic receptors and possibly also P2X-purinoceptors. The major postsynaptic subtypes involved were well predicted by mRNA expression as measured by RT-PCR, suggesting that this technique may be a useful adjunct to studies aimed at identifying functional receptor subtypes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Catecholamines / metabolism
  • DNA Primers
  • Electric Stimulation
  • Immunohistochemistry
  • Liver / blood supply*
  • Liver / innervation
  • Liver / metabolism
  • Mesenteric Arteries / innervation
  • Mesenteric Arteries / physiology*
  • RNA, Messenger / genetics
  • Rats
  • Rats, Wistar
  • Receptors, Adrenergic / classification
  • Receptors, Adrenergic / genetics
  • Receptors, Adrenergic / physiology*
  • Receptors, Neuropeptide Y / genetics
  • Receptors, Neuropeptide Y / physiology*
  • Receptors, Purinergic / classification
  • Receptors, Purinergic / genetics
  • Receptors, Purinergic / physiology*
  • Vasoconstriction / drug effects
  • Vasoconstriction / physiology


  • Catecholamines
  • DNA Primers
  • RNA, Messenger
  • Receptors, Adrenergic
  • Receptors, Neuropeptide Y
  • Receptors, Purinergic