Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Quantitative studies of the action of theophylline and papaverine were performed in rat epididymal fat pads, both on the lipolytic effect and on the activity of phosphodiesterase, adenylate cyclase and protein kinase. Papaverine, a stronger inhibitor of phosphodiesterase than theophylline, did not produce lipolysis. The maximum lipolytic effect (glycerol release) of theophylline was much higher than that of epinephrine and nearly approached the effect exerted by dibutyryl cyclic AMP. While theophylline potentiated or was without any effect on lipolysis produced by epinephrine and dibutyryl cyclic AMP, papaverine at concentration 10- minus 3 M reduced the effect of both drugs as well as of theophylline by 90 per cent. These concentrations of papaverine also strongly inhibited the activity of adenylate cyclase. Neither papaverine nor theophylline prevented the activation of protein kinase by cyclic AMP. The data suggest that the lack of a lipolytic effect of papaverine migth be caused by a combination of its inhibitory effect on adenylate cyclase and direct inhibition of activation of triglyceride lipase.
 ...
PMID:The absence of stimulation of lipolysis by papaverine, a strong inhibitor of phosphodiesterase. 16 81

1. Phasic and tonic components of the K+-induced contracture response were found to be expressed to different degrees in the prostatic and epididymal portions of the rat vas deferens. 2. With elevation of external potassium greater than 25 mM, the mechanisms underlying the phasic component operate only transiently before inactivation and replacement with tonic tension. 3. Both phasic and tonic components of the vas deferens response to potassium were markedly dependent upon external calcium ions. 4. Nifedipine and verapamil equally inhibited the phasic and tonic components of the K+ response in the prostatic vas deferens. However, inhibition by these agents was far more pronounced in the phasic components than in the tonic component of the epididymal vas deferens. 5. BAY K 8644 potentiated, in a dose-dependent manner, the phasic components of the K+ response, particularly in the prostatic vas deferens. 6. Abscisic acid also potentiated, in a dose-dependent manner the K+ response of rat vas deferens, but this action was far more pronounced in the tonic component of the epididymal portion. 7. Papaverine abolished the BAY K 8644 potentiated epididymal K+ response but did not affect the BAY K 8644 potentiated prostatic K+ response. 8. It is concluded that abscisic acid potentiated responses associated with the activation of voltage-dependent, non-inactivating slow calcium channels. 9. Papaverine, nifedipine and verapamil appear to be less selective than abscisic acid in that they equally inhibit phasic and tonic responses in prostatic vas deferens, but these may be interdependent, yet they more strongly inhibit phasic responses of epididymal vas deferens.
 ...
PMID:Voltage and time dependency of calcium mediated phasic and tonic responses in rat vas deferens smooth muscle--the effect of some calcium agonist and antagonist agents. 246 34

1. Frequency-response curves (0.1-30 Hz) were obtained in the epididymal portion of rat vas deferens. At low frequencies (0.1-1 Hz), the parameters evaluated were the first twitch and the fourth twitch at each frequency. The responses to trains of stimuli at intermediate (2-5 Hz) and high (10-30 Hz) frequencies were biphasic consisting of phase I (the first rapid phase of tetanus) and of phase II (the secondary slowly developing one). 2. Prazosin inhibited the first and the fourth twitch but not when the frequency was < 1 Hz. Suramin inhibited the first twitch while substantially depressing the fourth one. The combination of prazosin and suramin almost completely abolished all the twitches evoked by a train of stimuli at low frequencies. Nifedipine left almost unaltered the first twitch while markedly depressing the fourth one, especially at relatively high frequency (1 Hz). Verapamil was devoid of any inhibitory action. Papaverine depressed the first twitch while only at the highest concentration used (1 x 10(-4) M) markedly inhibited the fourth one. Chloroethylclonidine (CEC) depressed the first twitch and increased the fourth. 3. When intermediate (2-5 Hz) and high (10-30 Hz) frequencies are considered, prazosin and suramin partially inhibited both phase I and phase II, while in combination they almost completely abolished both phases. Nifedipine and verapamil selectively suppressed phase II, leaving phase I unaffected. Papaverine completely abolished both phase I and phase II. CEC was able to completely abolish phase I but increased phase II. 4. These results suggest that the response to the first twitch of a train at low frequency is prevailingly noradrenergic, prazosin-sensitive, while when the twitches are close enough (i.e. at 1 Hz) a summation of stimuli takes place and a predominant purinergic component, both suramin- and nifedipine-sensitive, becomes evident. 5. At high frequencies, both phases are due to the concomitant release of noradrenaline and adenosine triphosphate (ATP). The noradrenergic component of phase I is nifedipine-insensitive and CEC-sensitive, resembling the pharmacological profile of the endogenously released noradrenaline by single pulse, while that of phase II, nifedipine-sensitive and CEC-insensitive, is similar to that produced by exogenously applied noradrenaline.
 ...
PMID:Differential effects of drugs interacting with autonomic transmitters on responses of rat vas deferens to field stimulation. 1109 47