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C-terminal pancreatic polypeptide-like immunoreactivity in the rat forebrain
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}LqTION OF NEUROPEPTIDES ON THE OCIOPUS HEART K.H. Voigt, C. Kiehling, D. Fr~sch and R. Martin, University of U~u, D-79 Uhn, West Germany I_~munocytochemical evidence for the presence of "vertebrate" peptides Ln the neuropil of the vena cava of the octopus led us to study the action of neuropeptides on die octopus heart. The structural homology of the m o l l u s c ~ cardioexcitatory peptide FMRFamide, which was found to be present Ln the octopus neuropil, with ~nkephalLn precursor peptiHes is of particular interest. In vitro preparations of isolated octopus hearts and infusions into intact animals were used for structure activity studies. Substances were administered for I min and the h e a r t b e a t (&mplitude and frequency) was monitored. Extracts from dne octopus v~na cava neuropil and brain and from rat brains were purllied by gelchromatography ~nd HPLC. Only peptides c o n t a ~ i n g d~e C-termLnal sequence Arg-Phe-~H2 were potent in vitro (10 pmol/min); ~midation at ~he Cterminal-Phe residue was essential, Met- and Leu-analogues were nearly eTlipotent. Other presently known neuropeptides were inactive in vitro. Only eled o i s L n w a s a weak (100 ~ol/.min) heart stimulant. Purified extracts from octopus nervous tissue, but not from die rat brain, had very potent cardioexcitatory activity. As the opiate antagonist naloxone did not influence the activity of both d~e extracts and enkephalin analogues, it seems unlikely dnat opiate receptors are involved in the direct action on the heart. In dle free swishing octopus vasopressin exerted remarkable effects on ~ e blood pressure.
C-TERMINAL PANCREATIC POLYPEPTIDE-LIKE IMMUNOREACTIVITY IN THE RAT FOREBRAIN R.G. Williams, Physiological Laboratory, University of Liverpool, Liverpool,UK Although Pancreatic Polypeptide-Like Immunoreactivity (PPLI) has been described in rat brain, the identity of this material remains unknown since the specificity of the antisera used was poorly understood. Thus antisera to avian but not to bovine or human PP, demonstrated cells and fibres in the rat brain; however these antisera cross react weakly with rat PP. This work is a re-exmnination of the distribution of PPLI in the rat forebrain using a C-terminal specific antiserum which is known to react with rat PP. Rats were perfusefixed with 0.4% parabenzoquinone in cacodylate buffer and tissue was processed for the indirect immunofluorescence technique. In colchicine treated animals nerve cell bodies were localized to the following regions:- cortex, striatum, septum, nucl~us accumbens, tuberculum olfactorium, nucleus of the stria terminalis and hypothalamus. In addition, there were dense populations of beaded nerve fibres in the nucleus of stria terminalis and lateral septum; fibres were also abundant in nucleus accumbens, amygdala and hypothalamus. Scattered fibres were present in cortex, striatum, tuberculum olfactorium and thalamus. Localization was abolished following preabsorption with the C-terminal hexapeptide of PP (i0 nmol/ml) but was unaffected by preabsorption with FMRF-NH 2 at the same concentration. Conclusions. i. Molecules reacting with a Cterminal specific PP antiserum occur in cell bodies and fibres in rat brain. 2. Taken together with recent evidence that the C-terminal hexapeptide of PP has actions on central neurones (R.J. Gayton, personal communication), the present results suggest a neuroregulatory role for C-terminal PP-like peptides in the rat forebrain. C-terminal specific PP antiserum was generously donated by Dr. I.L. Taylor.
}LqTION OF NEUROPEPTIDES ON THE OCIOPUS HEART K.H. Voigt, C. Kiehling, D. Fr~sch and R. Martin, University of U~u, D-79 Uhn, West Germany I_~munocytochemical evidence for the presence of "vertebrate" peptides Ln the neuropil of the vena cava of the octopus led us to study the action of neuropeptides on die octopus heart. The structural homology of the m o l l u s c ~ cardioexcitatory peptide FMRFamide, which was found to be present Ln the octopus neuropil, with ~nkephalLn precursor peptiHes is of particular interest. In vitro preparations of isolated octopus hearts and infusions into intact animals were used for structure activity studies. Substances were administered for I min and the h e a r t b e a t (&mplitude and frequency) was monitored. Extracts from dne octopus v~na cava neuropil and brain and from rat brains were purllied by gelchromatography ~nd HPLC. Only peptides c o n t a ~ i n g d~e C-termLnal sequence Arg-Phe-~H2 were potent in vitro (10 pmol/min); ~midation at ~he Cterminal-Phe residue was essential, Met- and Leu-analogues were nearly eTlipotent. Other presently known neuropeptides were inactive in vitro. Only eled o i s L n w a s a weak (100 ~ol/.min) heart stimulant. Purified extracts from octopus nervous tissue, but not from die rat brain, had very potent cardioexcitatory activity. As the opiate antagonist naloxone did not influence the activity of both d~e extracts and enkephalin analogues, it seems unlikely dnat opiate receptors are involved in the direct action on the heart. In dle free swishing octopus vasopressin exerted remarkable effects on ~ e blood pressure.
C-TERMINAL PANCREATIC POLYPEPTIDE-LIKE IMMUNOREACTIVITY IN THE RAT FOREBRAIN R.G. Williams, Physiological Laboratory, University of Liverpool, Liverpool,UK Although Pancreatic Polypeptide-Like Immunoreactivity (PPLI) has been described in rat brain, the identity of this material remains unknown since the specificity of the antisera used was poorly understood. Thus antisera to avian but not to bovine or human PP, demonstrated cells and fibres in the rat brain; however these antisera cross react weakly with rat PP. This work is a re-exmnination of the distribution of PPLI in the rat forebrain using a C-terminal specific antiserum which is known to react with rat PP. Rats were perfusefixed with 0.4% parabenzoquinone in cacodylate buffer and tissue was processed for the indirect immunofluorescence technique. In colchicine treated animals nerve cell bodies were localized to the following regions:- cortex, striatum, septum, nucl~us accumbens, tuberculum olfactorium, nucleus of the stria terminalis and hypothalamus. In addition, there were dense populations of beaded nerve fibres in the nucleus of stria terminalis and lateral septum; fibres were also abundant in nucleus accumbens, amygdala and hypothalamus. Scattered fibres were present in cortex, striatum, tuberculum olfactorium and thalamus. Localization was abolished following preabsorption with the C-terminal hexapeptide of PP (i0 nmol/ml) but was unaffected by preabsorption with FMRF-NH 2 at the same concentration. Conclusions. i. Molecules reacting with a Cterminal specific PP antiserum occur in cell bodies and fibres in rat brain. 2. Taken together with recent evidence that the C-terminal hexapeptide of PP has actions on central neurones (R.J. Gayton, personal communication), the present results suggest a neuroregulatory role for C-terminal PP-like peptides in the rat forebrain. C-terminal specific PP antiserum was generously donated by Dr. I.L. Taylor.