Somatostatin induced hyperpolarization of septal neurons is not blocked by pertussis toxin - PubMed (original) (raw)
Somatostatin induced hyperpolarization of septal neurons is not blocked by pertussis toxin
M J Twery et al. Eur J Pharmacol. 1991.
Abstract
The coupling of postsynaptic somatostatin receptors to pertussis toxin (PTX) sensitive guanine nucleotide regulatory proteins (G proteins) was investigated in dorsolateral septal nucleus (DLSN) neurons using a submerged brain slice preparation and intracellular recording techniques. Rats were pretreated with PTX i.c.v. and neuronal responsivity to somatostatin and baclofen, a selective GABAB receptor agonist, tested using a submerged brain slice preparation and intracellular recording techniques. In tissue obtained from rats pretreated with PTX (2.5 micrograms) for 2-5 days, somatostatin applied by superfusion (0.1 microM) produced membrane hyperpolarization and decreased the membrane resistance of DLSN neurons. Hyperpolarizing effects of somatostatin persisted in the presence of tetrodotoxin (0.3 microM) blocking synaptic transmission. Current-voltage relations of the somatostatin-induced, PTX-resistant hyperpolarization indicated a reversal potential close to the equilibrium potential for potassium ions. Membrane hyperpolarizations in PTX treated tissue were similar to those recorded in tissue from vehicle control or untreated rats. Hyperpolarizing responses to the selective GABAB receptor agonist baclofen, however, were blocked by the PTX treatment used in the present study. Our findings suggest that the postsynaptic inhibitory effects of somatostatin in the DLSN is not mediated by a somatostatin receptor coupled to PTX-sensitive G proteins. These G proteins, however, appear to be an essential link in the postsynaptic GABAB receptor-mediated response of DLSN neurons.
Similar articles
- Somatostatin depresses GABA receptor-mediated inhibition in the rat dorsolateral septal nucleus.
Twery MJ, Gallagher JP. Twery MJ, et al. Brain Res. 1990 Jun 11;519(1-2):277-86. doi: 10.1016/0006-8993(90)90089-t. Brain Res. 1990. PMID: 1975766 - Adenosine inhibits the synaptic potentials in rat septal nucleus neurons mediated through pre- and postsynaptic A1-adenosine receptors.
Hasuo H, Shoji S, Gallagher JP, Akasu T. Hasuo H, et al. Neurosci Res. 1992 May;13(4):281-99. doi: 10.1016/0168-0102(92)90040-j. Neurosci Res. 1992. PMID: 1352869 - Muscarine increases a voltage-independent potassium conductance through an M4 receptor in rat dorsolateral septal nucleus neurons.
Hasuo H, Akasu T, Gallagher JP. Hasuo H, et al. Neurosci Lett. 1995 Apr 21;189(3):163-6. doi: 10.1016/0304-3940(95)11483-d. Neurosci Lett. 1995. PMID: 7624035 - Direct coupling of the somatostatin receptor to potassium channels by a G protein.
Yatani A, Birnbaumer L, Brown AM. Yatani A, et al. Metabolism. 1990 Sep;39(9 Suppl 2):91-5. doi: 10.1016/0026-0495(90)90220-7. Metabolism. 1990. PMID: 2169576 Review. - Activities of neurons within the rat dorsolateral septal nucleus (DLSN).
Gallagher JP, Zheng F, Hasuo H, Shinnick-Gallagher P. Gallagher JP, et al. Prog Neurobiol. 1995 Apr;45(5):373-95. doi: 10.1016/0301-0082(95)98600-a. Prog Neurobiol. 1995. PMID: 7617889 Review. No abstract available.
Cited by
- Somatostatin inhibits excitatory transmission at rat hippocampal synapses via presynaptic receptors.
Boehm S, Betz H. Boehm S, et al. J Neurosci. 1997 Jun 1;17(11):4066-75. doi: 10.1523/JNEUROSCI.17-11-04066.1997. J Neurosci. 1997. PMID: 9151723 Free PMC article. - Modulation of high voltage-activated calcium channels by somatostatin in acutely isolated rat amygdaloid neurons.
Viana F, Hille B. Viana F, et al. J Neurosci. 1996 Oct 1;16(19):6000-11. doi: 10.1523/JNEUROSCI.16-19-06000.1996. J Neurosci. 1996. PMID: 8815883 Free PMC article. - Operational characteristics of somatostatin receptors mediating inhibitory actions on rat locus coeruleus neurones.
Chessell IP, Black MD, Feniuk W, Humphrey PP. Chessell IP, et al. Br J Pharmacol. 1996 Apr;117(8):1673-8. doi: 10.1111/j.1476-5381.1996.tb15338.x. Br J Pharmacol. 1996. PMID: 8732275 Free PMC article. - Localization of the somatostatin receptor SST2A in rat brain using a specific anti-peptide antibody.
Dournaud P, Gu YZ, Schonbrunn A, Mazella J, Tannenbaum GS, Beaudet A. Dournaud P, et al. J Neurosci. 1996 Jul 15;16(14):4468-78. doi: 10.1523/JNEUROSCI.16-14-04468.1996. J Neurosci. 1996. PMID: 8699257 Free PMC article.