Electrically evoked release of [(3)H]noradrenaline from mouse cultured sympathetic neurons: release-modulating heteroreceptors.
Cultured neurons from the thoracolumbar sympathetic chain of newborn mice are known to possess release-inhibiting alpha(2)-autoreceptors. The present study was carried out in a search for release-modulating heteroreceptors on these neurons. Primary cultures were preincubated with [(3)H]noradrenaline and then superfused and stimulated by single pulses, trains of 8 pulses at 100 Hz, or trains of 36 pulses at 3 Hz. The cholinergic agonist carbachol reduced the evoked overflow of tritium. Experiments with antagonists indicated that the inhibition was mediated by M(2) muscarinic receptors. The cannabinoid agonist WIN 55,212-2 reduced the evoked overflow of tritium through CB(1) receptors. Prostaglandin E(2), sulprostone, and somatostatin also caused presynaptic inhibition. The inhibitory effects of carbachol, WIN 55,212-2, prostaglandin E(2), and somatostatin were abolished (at the highest concentration of WIN 55, 212-2 almost abolished) by pretreatment of the cultures with pertussis toxin (250 ng/ml). Several drugs, including the beta(2)-adrenoceptor agonist salbutamol, opioid receptor agonists, neuropeptide Y, angiotensin II, and bradykinin, failed to change the evoked overflow of tritium. These results demonstrate a distinct pattern of presynaptic inhibitory heteroreceptors, all coupled to pertussis toxin-sensitive G proteins. The lack of operation of several presynaptic receptors known to exist in adult mice in situ may be due to the age of the (newborn) donor animals or to the culture conditions.
Göbel
I
I
Pharmakologisches Institut, Freiburg im Breisgau, Germany.
Trendelenburg
A U
AU
Cox
S L
SL
Meyer
A
A
Starke
K
K
D000200:Action Potentials; D058666:Adrenergic beta-2 Receptor Agonists; D000818:Animals; D000831:Animals, Newborn; D002186:Cannabinoids / Q000494:pharmacology; D002478:Cells, Cultured; D018679:Cholinergic Agonists / Q000494:pharmacology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D004558:Electric Stimulation; D051379:Mice; D008815:Mice, Inbred Strains; D009292:Narcotic Antagonists; D009474:Neurons / Q000378:metabolism*; D009479:Neuropeptides / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D037342:Pertussis Toxin; D011458:Prostaglandins E / Q000494:pharmacology; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic / Q000378:metabolism; D017661:Receptors, Presynaptic / Q000378:metabolism*; D013004:Somatostatin / Q000494:pharmacology; D013564:Sympathetic Nervous System / Q000166:cytology / Q000378:metabolism*; D014316:Tritium; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D058666:Adrenergic beta-2 Receptor Agonists; D002186:Cannabinoids; D018679:Cholinergic Agonists; D018680:Cholinergic Antagonists; D009292:Narcotic Antagonists; D009479:Neuropeptides; D011458:Prostaglandins E; D043585:Receptor, Muscarinic M2; D011976:Receptors, Muscarinic; D017661:Receptors, Presynaptic; D010566:Virulence Factors, Bordetella; D014316:Tritium; D013004:Somatostatin; D037342:Pertussis Toxin; D009638:Norepinephrine